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First of all, an actively oozing saguaro wound of any type leaking a smelly dark brown or black liquid is almost always caused by bacterial necrosis. There are not really “three possible causes” for black sap dripping down a saguaro cactus trunk. What caused the necrotic tissue can be any one of several factors, but in the final analysis it’s usually bacterial necrosis (Erwinia cacticida, literally “Erwin’s cactus killer”) that is causing the damage, which left untreated can lead to the death of the cactus. What follows below is a fairly comprehensive tutorial on how to understand, diagnose, and treat Erwinia infections….
Bird saliva has nothing to do with causing the darkening of cactus flesh. While it is true that when a bird (usually one of two species, Gila woodpecker or northern flicker) excavates a nesting cavity into a cactus, that there are indeed bits and pieces of blackish cactus flesh being tossed out of the hole that land on the ground or nearby spines along the trunk. However this darkening is not caused by the bird’s saliva. Instead, chemicals inside the cactus’ tissues oxidize and darken, very similar to how the cut surfaces of apples or peaches turn brown when exposed to air. If you cut off a saguaro arm, or otherwise wound a saguaro cactus stem, you will see this darkening within minutes of exposure of the green flesh to air. This is why the stems may turn black, not due to bird saliva.
The photo above shows two saguaros at my property at D:F Ranch that were planted in 2008. I called them the Havasu Twins. They were originally planted close together in the same hole in Lake Havasu City, AZ in the 1970s by one of the co-founders of the city back when it was being first built from nothing; but they had to be relocated due to a remodeling of that home, so I adopted them and separated them by about 10 feet. The one on the left shows a bird hole in August 2014, which has callused over and is not a problem other than that it is somewhat unsightly. Unfortunately the one on the right has developed bacterial necrosis and would die by Sept 2014. Photos of that process will be added below as I illustrate the points I make.
Here is another photo of a different saguaro cactus at D:F Ranch which I added a short time after I made my original post. I realized that I could get photos of some of this black flecking due to bird excavation activity, and decided to obtain them and add them to the text for educational purposes. This is a northern flicker (Colaptes auratus) at the entrance of a saguaro cavity which it drilled into this plant earlier, approximately in October and November 2017. See how there are small granular bits of blackened cactus tissue clinging to the spines around and beneath the hole? These particles have been clinging here for months, and also littered the ground. As stated above, the blackness is caused by oxidation and has nothing to do with bird saliva. Nor is there in this case any oozing necrotic liquid – fortunately! No treatment is necessary, although if there was some sort of oozing sap I would definitely do something, a point to which I will be getting shortly….
This image shows this male northern flicker (formerly known either as gilded flicker, or yellow-shafted flicker) peering at me from its saguaro hole. This view shows the blackened bits of former saguaro cortical tissue stuck to the spines around the hole. Additionally, the bird’s tunneling activity has thinned the saguaro’s stem beneath the entrance to the point where it has died, shown as a yellowish dried out patch. While damaging to the saguaro’s apex, and aesthetically annoying to me, it’s also not fatal. There is no sign of rotting and therefore no particular action needs to be taken at this time.
Here are just a few more pictures of the flicker’s activity on the early morning shortly after sunrise in April 2018 when I took them. This male flicker was clearly nervous about my presence less than 30 feet away, and kept leaving the nest cavity to go perch on the dried flower spike of a nearby agave. But he would only stay there for 20 to 30 seconds before flying back to the nest. This motivation to return to the nest despite my close presence indicates to me that he might be helping to incubate eggs or rear young chicks, although I can’t verify this without potentially harming them if they are present. In any case once I had my photos, I left him to his day undisturbed.
Since much of Phoenix and western Arizona all the way down to the Colorado River zones are low in elevation, these types of very hard freezes are exceedingly rare, and as a result they are probably almost never the cause of Erwinia attack. Freezing resulting in damage that can leave saguaros more vulnerable to Erwinia attack is more likely to occur in the higher elevation portions of the saguaro’s range, such as around Tucson or the northern areas of metro Phoenix. But even there, saguaros grow abundantly in the wild and the local populations are periodically exposed to such cold spells, and are therefore more resistant to frosts and bacterial attacks. This is not to say that an extremely rare weather event such as a record-setting Arctic blast that may occur only once every 20 or 30 years can’t happen, but overall, damaging frosts are by definition rare in saguaro country, because if they were too regular an occurrence, the plants couldn’t survive there in the first place. The point is that frost damage can indeed be a factor that damages and weakens some saguaros to the point where Erwinia can attack them, but not every plant, not every year, and not in all microclimates within saguaro terrain.
What it boils down to in my opinion as a cactus grower and saguaro mover is this: Any liquid seeping down the trunk or out of some wound in any of your cacti (saguaros, organ pipes, barrel cactus, etc) is cause for immediate action. Don’t assume that a bird harmlessly caused it by saliva, or that it’s untreatable due to past cold snaps. Actively oozing wounds are almost always bacterial necrosis, and regardless of the initial triggering mechanism, they should be treated immediately upon noticing. I’ll get to how to treat infections in a minute.
If you do see a new bird hole in one of your domestic saguaros and there is no oozing, assume it’s okay for now, even if there are black bits of cactus flesh strewn everywhere as a result of their excavation processes. (See photos above.) Woodpeckers and columnar cacti have evolved together for a long time and most cacti do not get bacterial necrosis as a result of bird nesting activities, although this is not impossible. Again, if you do see liquid streaming down the trunk, act accordingly. As a general rule, old bird holes are safe (as in the left Havasu Twin in the photo I posted above) since the saguaro will have isolated the damaged internal tissues around the nest cavity by forming a hard, thick callus. Pay attention to new bird holes until calluses can form (as illustrated by the woodpecker holes I also just discussed) and as always be vigilant for surfacing problems and behave accordingly.
As stated above, the right saguaro of the Havasu Twins has developed Erwinia rot. Here is a photo of a lesion on the trunk that is starting to ooze sap, which has a foul smell and is running down the epidermis. At this stage, a lesion might not even be noticed by the average homeowner who is not paying close attention, but ideally, now would be the best time to treat the problem since it is still small and limited in scope. Early treatment would bode reasonably well for survival of the saguaro.
Here’s another image of what a homeowner might see in the early stages of bacterial rot: Thin lines of sticky black sap running down the trunk of what appears to be an otherwise healthy cactus. This is admittedly pretty easy to miss, but it’s important that if you do see it to get right down to treatment. These thin drainage lines may be coming out of a bird hole even. The advice Mr. Leblanc gave above of ignoring it if it comes from a bird hole is rather silly since clearly, this is not normal and needs urgent attention!
The lines of sap in the prior photo were originating from this wound above. Located beneath one of the saguaro’s arms, this is a very serious situation, as the necrotic zone is now quite large and deep, and might already be invading the core of the plant behind the ribs. Again, specific recommendations for treatment will be discussed below, but I wanted to add this photo to show a progression series of necrotic lesions so that the reader might better grasp what to look for and how to handle it.
If your cactus experiences a severe freeze and starts dying back a few weeks or months later, and there is no black oozing, chances are that the cactus is successfully isolating the frostbitten damage from the healthy tissues and may well survive, although with obvious damage. Again, the dying tissues might be tan, yellow, or brown, pale or dark, depending upon species, but if there’s no liquid infection with black sap draining down the trunk, the cactus is probably handling the damage just fine. It’s the active oozing that is the concern, less so than the simple presence of dead tissues as long as they are dry and scabby. Eventually the dead tissues will flake off and you can assist the process sometimes by pulling the scabby parts away down to clean, dry callus. Frost damage is permanent and will never fully heal over in many cases, but absent necrosis, it isn’t necessarily fatal to your plants.
However it is worth remembering that frostbitten cacti often do develop Erwinia problems, and that it is the frost damage that started it and the bacteria that can finish it. To treat frost damage as separate and unrelated to bacterial attacks is nonsensical to me, and I don’t know why Mr. Leblanc tries to diagnose them separately when in fact they are often related. Similarly, bird activities can also set off an Erwinia attack, and you should not assume based upon his faulty correlations that just because sap is draining out near a bird hole that it shouldn’t be treated. Oozing sores are always of concern, regardless of what originally started it, because oozing indicates that Erwinia has moved in, and that needs to be treated urgently.
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Lastly, some advice on how to treat Erwinia cacticida necrosis: Sometimes cacti can develop a small lesion infected with the bacteria and will successfully handle it without intervention. A small amount of oozing might occur that never worsens and the cactus’ immune system handles it. If that happens and a lesion develops and gets managed without your help, consider yourself lucky. But if you notice it you should ideally act on it sooner rather than later.
There are a couple of common treatments for Erwinia attacks. One is to spray isopropyl rubbing alcohol straight onto the wound, directly at the full strength it comes from the bottle in. (It’s usually 70%, but some cheaper brands are 50%, and perhaps 100% is also available at times. All will work, but 70% is the most commonly sold.) The other treatment is to mix a solution of 10% household chlorine bleach (about 1 part bleach to 9 parts water or so) and spray that into the lesion. Do not mix the chlorine and alcohol together, as dangerous chemical reactions might occur. Use one or the other, separately on different days, never together at the same time. There are no other pesticides sold that are known to be effective against Erwinia, so your best bets are these household remedies using commonly available and inexpensive chemicals and a bit of your own effort.
It usually helps to use an old spoon or other metal tool to scoop out any rotting black tissue in the wounded area before you start spraying. Or you can also use a sharp knife to carve out the damage, cutting cleanly down to fresh green tissue. Scoop the rotting flesh into a bucket, plastic bag, or container of some sort rather than letting it fall onto the soil if at all possible, and dispose of the rotten material in the garbage, not the compost heap. Get as much of it as possible, again down to firmer fresh green tissues, and then spray either the alcohol or the chlorine once the wound is cleaned out. Avoid making punctures in the unaffected flesh, as the bacteria can survive in those wounds and not be reached by the chlorine or alcohol spray. It is also prudent to make the base of the carved-out portion into the shape of a V that drains downwards, which will prevent any further sap or rainwater from pooling at the base of the wound.
Unfortunately, it is also a truth that sometimes Erwinia infections occur with great speed, or while homeowners are away for summer, or below soil level, or infect the inner core of the plant before it’s visible on the surface. In these cases, there may be little to be done and the cactus is a total loss, in the same way that sometimes cancers are not detected before they are untreatable and fatal. If you want to try to reverse-engineer the potential stress factors that might have led to the cactus getting Erwinia to such a degree, then that might be a worthwhile exercise in order to correct problems and prevent further spread to other nearby plants. But it’s a bit foolish to try to determine “harmless oozing liquid” from “deadly oozing liquid”, and that bit of misinformation was what I wanted to correct. 😉 All oozing liquid is bad.
In the case of the Havasu Twin saguaro above, the rot was already systemic, and occurred at the base, right at and below the soil line. For this plant, it is way too late as the rot has already ringed the entire trunk and separated the top from the root system, and the saguaro is going to die regardless of treatment options. The only answer now is to cut the entire plant down and haul it away. The photos of the suppurating sores I posted above are examples of less serious infections that might actually occur absent the basal decay shown here, and if they were isolated small patches of necrosis then the odds of successful treatment and cactus survival would have been good. But in this case I knew the rot was systemic and spreading up the core of the plant and that within a few months at most the entire plant would brown and collapse into a slimy, nasty mess. However I decided to document the death process for educational purposes so that I could someday write a blog post like this one. 😊
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On disposing of a fatally infected cactus: Try to not contaminate too much of your gravel or soil with the foul smelling sap which is riddled with bacteria, lest you spread it to other cacti. Erwinia can attack other cactus species but is most dangerous to larger species such as barrels, saguaros, and other generously-sized cacti, although chollas, prickly pears, etc, can get it too. Agaves, aloes, yuccas, etc are not vulnerable to it as far as I know.
If a given infection has clearly spread around the entire trunk base of a saguaro, I recommend cutting the entire plant down ASAP and removing the still-green top parts well before they start rotting too. This is because fewer bacteria means lower risk to nearby plants, and less disgusting mess to clean up in a few weeks when it inevitably consumes the entire plant anyway. If the lesion is on a saguaro arm but nowhere else, sometimes sacrificially cutting off the arm is workable, although I would treat the cut surface where the arm used to be with alcohol or chlorine just to be sure, rather like a vaccination. Ditto with the top – if a cactus’ main top stem is infected but lower down it is still healthy, cutting the top off and spraying can often save the plant, although it will obviously be deformed thereafter. (But it would be anyway, since Erwinia often kills part of a plant but not always all of it.)
As it would turn out, in only one more month the “walking dead” Havasu Twin saguaro would actually collapse and fall over in a heavy rainfall event inspired by the remnants of Hurricane Norbert, which passed over the desert southwest on Sept 7 and 8, 2014. My part of Arizona received widespread amounts of rainfall exceeding an inch, with D:F Ranch itself receiving 2.1 inches (53 mm) of rainfall in one day. The saturated soils and accompanying winds combined with the weakened rotten base meant the final demise of one of the Havasu Twins. But the storm didn’t cause the death, since I was expecting the fall to occur at any point and it could just as easily have happened on a mild, sunny day given the trajectory of the necrosis.
Fortunately the saguaro missed most of my other garden plants when it thudded to the ground. I did lose a small barrel cactus that was unluckily growing right nearby after the saguaro landed on top of it and crushed it.
Cutting off the entire top of an infected saguaro however only makes sense if there is absolutely zero sign of core rot or discoloration in the innermost regions of the cactus. If it is clean and whitish-green and firm, then there’s a chance that things will be okay. Spray preventively anyway. However if there is any sign of tan, brown, or black rot in the middle, then just finish the job and cut the entire thing down. It’s sad, but necessary, and will probably be best for nearby plants and your wallet anyway.
I would not recommend replanting another saguaro or other cactus species into the hole left behind when a saguaro dies of bacterial necrosis. The risk of the new cactus also getting it from contaminated soil is too great. I would recommend moving the new cactus to a spot a minimum of 6 to 8 feet away, farther if possible, and planting a different species (not a cactus) in the old hole, or simply filling it in and leaving the space open. One possible exception might be that a saguaro was removed preemptively without the infection having had a chance to leak down into the soil, and therefore the soil is reasonably clean. That might be okay. But if there was significant soil pollution with leaking black sap, then it’s a poor bet to make, as there is no simple or reliable way to decontaminate soil from Erwinia that has discolored it. (Aside from time, of course.) And plunging a brand new cactus with a damaged and stressed out root system from a transplant directly into a hole filled with contaminated soil is simply asking for trouble.
Removal of a fallen saguaro cactus, whether already rotting or simply dropped by a windstorm or by the necessity of new construction or other concerns, is a somewhat tedious and laborious process. It’s not particularly difficult in some ways, as the soft succulent flesh is easy to cut with a hand saw in a way that truly woody tree trunks are not. The woody skeletal base and the ribs of the central part of the trunk are admittedly more difficult to cut through with hand tools than the softer top is, but with enough persistence it can be done.
My two main tools in chopping up a saguaro are a sharp hand saw and a pair of hay hooks, used to heft hay bales around. The saw is obviously used to cut the stem into manageable sized segments like a giant zucchini. I usually try to make the slices weigh not more than 50 lbs, although some of the thickest central portions might approach 100 lbs. The hooks make it much easier to lift the slimy, slippery, and spiny stem pieces into the trailer. Since trying to preserve the skin in a pristine condition is clearly not a concern, I typically just jab the hooks into the sides of the cactus at random and throw them around. The goal is disposal, not replanting a prized landscape specimen….
By the way, note how the cut surface of this upper portion of the stem is “clean”, meaning whitish green and showing no signs of internal rotting or discoloration. This is the color you should be looking for when cutting away infected portions of trunk, or in cutting back a necrotic top to clean trunk beneath. In this particular example, of course, the plant was dying and would eventually have rotted regardless, but in less doomed plants this fresh clean greenish white tissue is what you would look for. And then do a preventative spraying of bleach or rubbing alcohol to kill any bacteria that may have been transmitted in the cutting process.
However as I progressed with slicing the trunk into segments, note how the rot suddenly appears in the central core of the plant and the fermenting liquid spills out onto the soil surface, contaminating it.
A saguaro that has systemic Erwinia rot will often experience total liquefaction of the internal water-storing tissues. This is what you see dripping down the trunk and pooling on the soil surface when you remove a saguaro with advanced decay. Teeming with billions of bacteria, this gross liquid is hazardous to nearby cacti as it is a potential source of infection for them as well. If it is possible to avoid contaminating your soil this way, it’s advisable to do so. In my case it was not, but if so, try to not do this.
Once again, not all of those oozing sores are necessarily indicative of core rot however, so treatment is still of value in many cases, especially when they are just on the surface and have not yet penetrated beneath the ribs. I knew this plant had systemic rot back in August 2014 in the first photos, and I was totally expecting to see this sort of decay pattern, but the take home point is to understand that while bacterial necrosis is an urgent situation, that it is not necessarily fatal if caught early and treated quickly.
The Havasu Twin saguaro, after it has been sectioned up and loaded into the trailer for disposal in a safer place where hopefully it won’t be able to infect any other plants. I was doing this removal job just in advance of the arrival of yet another cyclonic-remnant storm system from former Hurricane Odile, which pushed across the desert southwest on September 16, 2014. I wanted to clean the rotting saguaro up before the predicted heavy rains would delay me any further.
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Erwinia cacticida is a natural pathogen, native to the Sonoran Desert ecosystem, and healthy cactus plants have some resistance to it since it is present in the environment whether we like it or not. It can sometimes be a bit of a mystery as to why one saguaro develops a raging case of fatal necrosis within weeks, while nearby ones live on for decades more, unaffected by their stricken neighbors. Necrosis can strike weakened plants more readily than ones that are vigorous. Stressors might include a cold snap the prior winter (as discussed above), extreme summer heat, long-term drought in years where rainfall is well below average, excessively wet years, too many bird holes, and transplanting in the case of domesticated saguaros that just underwent a move. There is no one single cause for Erwinia attacks, in other words, which is why diagnosis can be somewhat confounding. The better course of action is to be mindful, watch for oozing sores and dripping sap, and to treat promptly upon discovery.
I hope that this blog essay will help readers understand what the causes of bacterial necrosis are, and help everyone to better intervene should the disease surface in a saguaro you know and love near you. It’s worth understanding how to manage the disease in the interests of saving the long-lived saguaros and other valuable cacti we so appreciate in Arizona and elsewhere.
Probably the best written piece on bacterial necrosis I have read. Very thorough and will illustrated. Unfortunately it has confirmed that my 6 foot saguaro has this condition all around the stem and will need to be removed. The condition happened very quickly since I look at it fairly closely every week or two. Would wish to replace it with another sagaro in the same area. but you have convinced me that is highly risky. Thank you for authoring this article.
That is too bad to hear, although it does simply happen regardless of our best efforts at times. It is true that sometimes the necrosis happens with alarming speed. If a plant for some reason develops the infection internally or in a hidden spot and it spreads rapidly up and down the vascular system of the trunk before finally becoming evident on the surface, then there is nearly nothing one can do about it. My goal in writing the article was to show how to deal with more readily evident surface signs of problems and act accordingly. But the bacterial rot doesn’t always cooperate with our intentions, sadly. 🙁
I enjoyed reading your article very insightful and the pictures helped immensely! With that said I unfortunately have a massive 25-30 foot-ish saguaro that is starting to ooze from the base. It’s just the ooze stage but is this non salvageable? It seems that way but perhaps I’d ask. Another concern is the cactus is close to my house 10feet or so. It is still up right for now, any tactical way to trim before collapse?
Thank you again for the article and clarification on all the possible scenarios.
Treat immediately as described in the article and hope for the best. But if that fails and the rot spreads, you may indeed want to just preemptively take the saguaro down before it gets to the point of collapse on its own. Is the saguaro leaning in any particular direction that you can discern? If so, that is the way it is most likely to fall for obvious reasons. If that is towards the house to any degree, preventative removal is probably the smartest option. If not then you can assess whether the likely direction of fall will damage anything else nearby of value, whether another plant or plants, terraces, art, pools or fountains, etc. If the damage potential seems too great, just cut it down. Professionals should be able to do it for you for a few hundred dollars or so (not sure of local rates) which is a lot less costly than fixing a roof or pool. Good luck.
Your article on bacterial necrosis was just what I was looking for.
New to Arizona, we bought a house in Scottsdale in late 2018. There were two saguaros out front. Both had suffered substantial damage but one had the notorious black sticky liquid streaking the lower half. I was to learn this was bacterial necrosis. And you’re right: When the infection really takes hold, the saguaro succumbs with astonishing speed. I would come outside in the morning every other week to find that another arm had fallen off in the night. Now the saguaro is completely dead. I don’t think it will be standing much longer. It has horizontal cracks along the base.
I know what caused the decline. The former owners had planted these saguaros in a zone with plants that were getting watered 3 times a week. So, the classic overwatering.
As a non-horticulturist, can I cut up and dispose of the dead saguaro on my own?
Thanks again for the article.
Sorry to hear about the loss of your cactus. It’s always a bit sad and it’s not always possible to treat bacterial necrosis even if you notice it very early, which many people do not.
Yes, you can cut up the cactus yourself for disposal, no need to worry about permits or legality since once you own a given plant, especially if it dies, you are free to do what you want with it. If it is still very liquid and gross, it will be messy to clean up and I would maybe consider waiting until that slime and decay dries up and goes away in a few more weeks. On the other hand, if it is not too bad yet along the main trunk (in terms of rot, not death because the latter has already occurred) then it might be worth cleaning up before it starts to get disgusting and contaminates the soil with the leaking liquids and black oozing sap.
Remember to not risk planting another saguaro or other cactus species in the spot where your dead saguaro is. There is a good chance that soil contamination with the bacteria will infect and kill any new installations, so if you want a replacement plant use a different non-cactus succulent (yucca, ocotillo, century plant) or desert tree (mesquite, palo verde, ironwood, etc) in its place. The bacteria won’t attack those types.
Great article! I have a saguaro cactus with this bateria and want to save it if possible. I live in Palm Desert CA and it is not possible to cut out infected parts because it would be half of the cactus. Is there a topical spray and special soil treatment that I can purchase to help save it?
There is no treatment commercially manufactured to specifically address this issue. I discuss the options available in the article in some detail but they are limited, and it is possible that your saguaro is already too far gone and might not be saveable. I also discuss what to do with the soil afterwards should it die: Basically you are limited to “don’t plant another cactus in place of the rotten one in contaminated dirt because it might just kill your new plant too”. Sorry to hear about the problems but it is a fact of desert gardening life. 🙁
I’m learning a lot from your blog. Great stuff! We are new to Arizona, and I hope you can help. We have two small saguaros, about 3 ft. tall that were transplanted by our landscapers from one area of our property to the front yard. The tops of the young saguaros are beginning to turn black. One of them was transplanted very close to the house near a corner wall by the landscapers. We do not water it. Is there something we can do to save it?
Assuming this is a recent move within the last few months, your plants need water after a transplanting because they have root damage. It’s an inevitable part of moving them that they lost most of their roots, and therefore their ability to absorb water. Forcing them to go through a Sonoran Desert summer without any water on a damaged root system is going to hurt or possibly kill them, so help them out.
This is true for any bare root cactus or succulent – you can’t expect them to suffer root trauma and no watering for many months in 100+ F heat and also look good, although damage manifests in different ways for different species – yellowing, dead scabby patches, leaf loss, radical dehydration and shriveling and shrinkage of body mass, and even death. You should probably also offer it some shade cloth (50% density is good) for the rest of the summer to stop further cell death causing the discoloration. It may not fix the damage that has already occurred, but can prevent further spread. Leave shade cloth on until at least late Sept until the weather cools off. But at the bare minimum, definitely water it at least 5 gallons every few days to week for the first couple of summers!
If your saguaro is less than 4 feet from the walls of the house, move it farther out because in the long run that is probably too close for plants that get as large as saguaros do. It will be difficult or impossible to move once it gets older and heavier and if it starts interfering with the house or roof line, then usually it is the plant that gets chopped down while otherwise perfectly healthy, just in a bad spot. Do it while it is still small and can be corrected.
One principle that I encourage everyone to observe is to plan ahead for vegetation to be able to reach a mature size, whatever that size is, and don’t plant cute little 5 gallon pots or small baby plants of large species that in a few years or decades will outgrow their allocated space and start interfering with things like houses, walls, porches, roof eaves, overhead power lines, other trees (including trees that are still small themselves right now), and so forth. Just as you shouldn’t plant an oak or pine that reaches 100 feet tall 3 feet from your house, nor should you plants a saguaro that will become 25 to 30 feet tall that close to it either. Give everything more space to avoid having to deal with an obvious problem in a few years. (And also don’t fall back on the old “Well it won’t be my problem because I only plan to live here for a few years anyway” notion. That’s frankly irresponsible. 😉 )
Thanks for a nice explanation of a sadly destructive process. I wondered if you had any recommendations for managing exposed saguaro ribs? Usually this seems to occur around the base, a section of flesh is lost but there is no evidence of infection. It remains dry and innocuous so I figured the plant knows best, so I’ve done nothing……Would application of pruning paint sealant be wise or is the process best left alone?
Sometimes saguaros suffer damage to the outer cortex of succulent water-storage tissue somewhere on the branches or trunk. Often it is lower down but it can more or less happen anywhere actually. If it is bad enough or deep enough this can lead to exposed woody ribs, as you mention. There may be several causes of this type of damage, with bacterial necrosis being one. But there can also be others – frost damage, sunburn, animals gnawing at the trunk for water, bird holes that grew beyond the initial excavation the woodpecker made, etc. Rabbit and rodent damage from gnawing for water in dry hot summers usually is within a foot or two of the soil line at the highest, bird holes are usually higher than 6 to 7 feet up the trunk, and frost or sun damage can be virtually anywhere, although frost is typically on the north face (colder in winter) and sunburn on the south or west face (hotter in summer). Any of these damage spots can be initiated by one factor and then made worse by a bacterial necrosis infection afterwards as well, so a combination of damage components is also possible.
Anyway, the point is that many saguaros that are in otherwise good health can sustain an injury and/or infection of some sort and isolate the damage without it going systemic and killing the entire plant. This appears to be what happened to yours. Of course that scar is ugly and permanent and unlike normal woody trees, the cactus will never be able to grow a new layer of bark over the wound and eventually heal that scarred area over. The ribs will always be visible unfortunately. But if the scar is dry and scabby and shows no signs of active rot or oozing sap, then the best thing is to leave it be and assume the plant’s immune system has handled the problem. There is no need to paint the wound or do anything to it, since the dry heat and air and sunlight of the desert usually aids in minimizing risk of further infections.
Many saguaros live for decades with such sizable scars and continue to grow and reproduce normally. Eventually, many years from now, the cactus will age and then it might die of a quite possibly unrelated issue, but this is not preventable and remember that nothing lives forever. For now, enjoy the plant and leave well enough alone. If you see a resurgence of infection somewhere else then treat accordingly as per my article above.
Great article – Thank You. Living in NE Phoenix we have been in our house 30+ years. 3 saguaros of various sizes are in the backyard, most likely since the 70’s. The largest one – 5 arms and gigantic had the bacteria about 25 years ago – it was cut out, treated with bleach and the cactus keep growing. It has it share of damages and birdholes, as well as bellowing hard dry cracking skin with exposed roots inside at the bottom, but so far so good. The 2nd largest one, about 35 feet tall, just recently within a matter of 10 days started to smell, turned black from the roots 3 feet up and then started oozing. I literally cut away 4 feet of diarrhea looking (and smelling) rot, exposed rinsed and bleached the skeleton and now I am curious if it even has a survival chance ? In the desert I have seen pretty poor looking saguaros with exposed lower skeleton areas, but it certainly looks off balance, if not dangerous. What balances or keeps the cactus up ?
The flesh is soft, the roots are pretty small, how does it stay up and withstand monsoon storms etc ?
Plants that large are obviously quite old and nearing the ends of their natural lifespans. You can probably prolong their life via intervention measures such as the removal of rotting tissue and bleach treatments, perhaps for a number more years. But sometimes the rot invades the heart of the plant within the woody rib cylinder, and takes it down anyway. If it was aged and large, it was perhaps close to time, similar to a person approaching 90 or 100 years old can be expected to go before too much longer.
If the saguaro is not near anything that it could damage when it falls (walls, houses, pools, cars, fences, other trees you care about, etc) then just treat and hope for the best. If it falls, it falls, and you can deal with it later. However if it is near something you want to preserve, you might want to take removal action now or soon, before it progresses to a point where it weakens and drops. The timing of it falling over is somewhat unpredictable and could occur with a storm, or just virtually at random even on calm days, so if it will harm something on its way down I’d deal with it now. Whatever direction it is leaning, even slightly, is almost surely the direction it will fall, so you can predict that to some degree. Calculate the risk based upon those factors as to whether controlled removal makes more sense or if you can just let nature take its course.
I am so grateful for this wonderful article. As a Phoenix native, growing up with saguaros was imprinted into my heart when I got my own place that was saguaro-less. I, sadly, learned the hard way of what happens when a saguaro moving company transplants these giants in the wrong orientation from how they originally grew. I used Roadrunner Cactus who brought me a 13 arm 25 Foot “Mom” saguaro and 2 offspring Spears (15 Foot each). The first spear about 6 months after transplant developed a sunburn, which quickly followed a yellowing/then dying of outside skin followed by the necrosis oozing the length of the cactus. Frenchie made several visits to my house, saying this spear was unlucky, and the other two would live but that wasn’t the case. Despite my incessant saguaro surgeries and bleach treatments to all 3, one by one, they all oozed putrid black ooze up and down the entire body until they fell, one by one. Upon my anger with this unforgivable mistake, the company found me 2 more homeless/unwanted saguaros (about 17 feet tall/armless) … “free” except for the transport/planting cost (still $1500 alone)… this was 2 years ago. Just yesterday, I see the largest of the 2 leaning and see the bottom Foot (half around the base) is completely spongy with a hairline crack oozing black again. This is the base of the cactus right around the root. I’m beside myself. Going thru this a 4th time is unconscionable … especially given there were 5 saguaros planted… I’m torn between turning this company into the ROC or daring to ask the owner to fix the mistake again of yet another bad planting job that costed the lives of (soon to be 4) epic saguaros? (Another cactus expert told me these were planted too shallow and exposed the root base to infection)… is that possible it would take a few years to get a root base infection years later from a bad planting job? (This is definitely not an issue of water, no water around these) Any recommendations would be helpful. I don’t know if I should even attempt to cut out the rot around the base if it will just make the oozing wound mess worse before having to cut it all down anyway. Is there any chance to even save with bleach if rot is at the base? If no hope, is there any way to salvage the skeleton as a whole? Thank you in advance. Even knowing I’m not the only one going thru this comforting… although I think losing 4 out of 5 saguaros from the same company is highly suspect. 😩
Your situation sounds complicated and very distressing. So sorry you have been going through this. I strongly suspect that there are actually multiple factors at play that are causing the deaths of your saguaros, ones that are separate initially from the necrosis, which is probably a symptom of poor transplanting advice and practices. I may have to someday address this issue in a different blog post, because how plants are moved in the first place has a tremendous effect upon their long-term survivability. I’ll try to answer at least a few concerns of yours in this comment however.
Orientation of a saguaro (or any other cactus or succulent) does play a role in survival, but it’s not as large as people suspect, and also can be mitigated in any case. Sometimes it is impossible to get the original south-to-south orientation correct again upon installation in a new spot, simply because of access issues at one or both sites (original and new) requiring a certain vehicular approach that can’t easily be modified. The main reason we want to fairly closely match reorientation is because it manages sunburn, which can result in dead patches of epidermal cells (the green “skin”) that are unsightly, and can occasionally lead to infection. Cells on the north side are often thinner and less UV- and heat-resistant than cells on the sunny south and west sides exposed to the most summer sun, so this is why this matters. But it’s not quite as deadly as people have been led to believe. (And my experience is that many saguaro movers and nursery people can’t even explain why orientation is considered to be so important – they just say that it is without really knowing why….)
The ways to avoid sunburn in plants where original orientation matching is not possible are several. Plants can adjust to a new orientation, even 180 degrees different, if they are assisted in making the transition. One way to help them is to move the saguaros (and again, any other plant) at a cooler time of year with shorter days – October through April are good months for transplanting when compared to intense summer heat the other May-September months.
A second thing people can do is to shade the plant the first summer with 50% or so shade cloth. Shade cloth is used in greenhouses, shade structures, carports, window screens, and so forth. It’s a sturdy woven plastic fabric that allows some sun to pass through (important for photosynthesis) but breaks the worst force of the summer UV and sun and heat. I would use not less than 30% shade cloth, meaning it blocks 30% of the sun, and not more than about 50%, because if it is too dark under there you are depriving the plants of needed light to make food via photosynthesis. Shade cloth is sold in rolls or squares at hardware stores like Lowes or Home Depot and doesn’t cost too much. Any color is okay although some people prefer the paler tan over black. I have used all colors (including red and green and white) and all are suitable for summer sun blockage.
It would be okay to drape a length of this shade cloth over the top of a saguaro, especially shorter ones of 10 feet or less. For taller ones, you might want to cut the pieces and wrap them around the arms and trunk and secure them with twine. This is most likely to be necessary for only the first summer, even if the plant was installed the autumn before. I would shade cloth any new plant installed in April or later simply because the days are getting longer and hotter quickly by then, and once sunburn happens, it cannot be fixed – the plant will always have a dead patch of scabby tissue on sunburnt areas for the rest of its life. This is why you want to avoid sunburn, for both aesthetic reasons and to limit infection points. Shade cloth can be removed in late September or early October and might not require replacement the next summer if the plants establish correctly. By the time the plants go through a second summer, odds are great that the cells are now used to UV and extra heat, and they will have effectively adopted a new orientation.
By the way, summer shade cloth as stated is helpful on many new plants, especially bare root succulents, including yuccas and barrel cacti. It reduces heat loading and slows down dehydration rates and opens a space for their recovery of the root system, which is by far the most important aspect of their ability to return and start growing again. Plants battling sunburn and desiccation and extreme heat won’t have the energy left over to form new roots, yet new roots are critical for absorbing water, which staves off dehydration. They can easily enter a negative death spiral, so this is why helping them out their first summer is so important.
Plants that are established in pots and have a root ball and soil are not nearly as sensitive to death as bare root ones are, so shade cloth is frequently not necessary for those. Especially not if they are planted in the cool season to allow for better establishment times over several months. Some species might want to be shade clothed in summer regardless (saguaros are not among them) simply because the Sonoran sun in July and August is too much for them, but the point is that most bare root new plants are best off if assisted that first summer, saguaros included. It is situational. I know shade cloth is ugly to look at in your yard or landscape, but a dead plant is even uglier, and an expensive dead plant the ugliest. So I recommend just accepting the temporary unattractiveness and doing it that first summer anyway since it can really pay off in better survival later on down the line. You may never have been told this, but it might have helped.
Moving on, there are also quite possibly other factors at play in your high death rate. The first is plant age. The bigger the saguaro, the older it is, obviously. But the older it is, the harder it is to successfully transplant them and get them to live for more than a year or a few. It’s like when you perform open heart surgery on someone who is 25, 45, or 85. As a general rule, the older person has a far higher death risk than the middle-aged one, and both are higher risk than the youngster. I consider any saguaro that is taller than about 20 feet and which has more than a few short arms to be a very poor long-term survival risk. Really tall, heavy plants with multiple long arms are impressive to look at in the wild or in a mature landscape, but they are the worst survival bets to transplant. This doesn’t mean some don’t successfully survive such a move, but the odds are simply much greater that fatal problems will surface on older and larger plants.
Spears are more likely to survive a move, IF (and this is extremely important!) they were dug properly and given proper follow-up care. All too many saguaro transplanters abuse the root system of their saguaros, chopping nearly all of the roots off and then plugging the plants into a deep hole, burying 2 to 3 feet of trunk for stability. Saguaros have a fairly extensive root system when they are intact, one that has several taproots that plunge several feet straight down into the soil for anchorage, and a bunch more shallow lateral roots that sprawl out perpendicular to the trunk and reside just a few inches beneath the soil surface. These lateral roots also provide anchorage but they are the ones most responsible for water absorption since a majority of desert rains are not going to wet the soil more deeply than about 12 inches, although if several storms arrive in quick succession the soaking will be deeper than that.
The plants grow both types of roots because they need them! But when we dig and bare root them, they lose a huge percentage of both types of roots, probably as much as 80% to 95% depending upon how much care is taken. You are asking a transplanted saguaro cactus to survive with 2 or 3 tons of top growth on perhaps as little as 5% to 10% of its normal root system. This is EXTREMELY hard on them, and no one should think otherwise. To be sure, with proper care and treatment they often can survive it, but do not underestimate how tough this is on the plants and how long it takes them to regain normal health. It annoys me when some movers say, “Oh don’t worry, saguaros are tough, they don’t mind being moved at all, they grow like weeds, you can’t kill them, etc.” None of this is true aside from the plants being tough. But not infallible. They have limits and undergoing a transplanting process is damn close to exceeding those limits even under the best of circumstances.
So the question becomes, did Roadrunner Cactus bother to preserve at least a couple feet of lateral roots and most of the length of the taproots? Or did they chop almost everything off before handing them over to you? I cannot say because I don’t know their operation style nor was I there. What I can say is that when I dig and transplant large saguaros, or anything else (ocotillos, Joshua trees, yuccas, agaves, etc) for that matter, I try to get at least a reasonable percentage of their roots. Again, these plants grow these roots because they need them, and when we deprive them of said roots by forcibly moving them (a thing they would not encounter ever in the wild) we have just made their next few years much more tenuous and difficult to survive. It is not possible to get all 30 plus feet of a mature saguaro’s lateral roots. But it is possible and should be mandatory to get a couple feet of them. Yes, you need to dig larger holes to accommodate those roots. But the survival rate is significantly improved.
If you are charging people thousands of dollars for plants, you should do everything to optimize survival rates. It’s best for the plants, it’s best for the clients, and it’s best for your own business reputation if you are a mover. Will all plants moved bare root survive? Unfortunately, no. But you can explain the risks to the customer based upon a realistic reading of plant health on a case by case basis. If a transplanter learns how to read each situation, they can tell the customer for example that this young or mid-sized spear has a good root system, and since we got a lot of the roots (maybe 40% to 50%), and we are planting in October at the start of the cool season, that the odds of this plant surviving are pretty high. Exact percentages are hard to assign, but a healthy spear with good roots moved in fall or winter and watered properly (more on that momentarily) and given shade cloth if needed the first summer might well have a 5 year survival rate of over 90%.
Conversely, if the assessment is a giant, aged, ancient saguaro with multiple arms moved in July and not given shade cloth and where 95% of the roots were left behind in the old spot, you can count on about a 90% chance of death in less than 5 years. I know this is unpleasant to have to tell people if you are a mover, but if you operate ethically, you should inform them of this. Best to say it up front, well before any money changes hands or any holes are dug. I always try to tell people, “I don’t think this plant is a good risk to be honest for various X and Y and Z factors, but if you really want me to attempt it I can do it. And here are the steps we should take to maximize the chances of success.” Surprisingly sometimes the customer still decides to proceed, and sometimes if I do everything possible correctly the saguaro does survive. But at least if it doesn’t make it, it’s not a negative surprise that leaves the customer feeling angry and disillusioned. It’s incumbent upon the transplanter to learn how to best present this information to their clients in my opinion, because most often the client themselves has absolutely zero idea of how to go about this. Why would they? You as the mover should help them understand. It’s in everyone’s best interests.
Finally, I have to address watering. By now it might be coming into focus that it is absolutely critical that newly transplanted succulents, saguaros or otherwise, do require follow up watering in order to survive. After all, they just lost a majority of their root system, kind of no matter what! No matter how carefully you dig large plants of this nature, it is inevitable to lose most of the roots. As explained above however, there is a significant difference between losing 60% of your roots and losing 95% of them, and the plant that lost fewer roots has a much better chance of faster recovery, if this is also paired with watering, shade cloth in summer, and proper time of year. You kind of need to line up several different factors for the best odds of success. It’s not just one thing or another, it’s the synergistic combination of all four things.
More to the point, watering is critically important even for saguaros which are among the most drought-resistant plants in the desert – in their intact, never-transplanted state. The equation changes radically for ones that got moved! From the plant’s perspective, the sudden loss of most of its roots represents an instantaneous and catastrophic onset of the most severe drought it has ever experienced. If you had to breathe on only 20% of the oxygen you are used to, you are in a dire emergency, right? Well for plants that lose their roots, the water situation is similarly desperate. This is why they need water. You cannot dump them into the ground, especially not in an Arizona summer, and fail to water them and expect them to thrive. HELP them out! Preserve at least some of their roots, and water the remaining ones they do have so that they can drink up the moisture and grow additional replacement roots. Do the move at a cooler time if at all possible and offer shade cloth that first summer if needed. It’s hard to emphasize how important this particular combination of treatments is in terms of getting your larger saguaros to survive.
As for watering amounts and frequency, this is an impossible-to-answer question in terms of it being one size fits all. But with proper understanding of some basics (this is very important for the transplanters, and also the new owners) it is possible to water within a general range of correctness and get far better results than if you ignore or don’t understand the issues at play. Perfection is not required and plants have a range of tolerance of dryness and wetness, including saguaros. But it is important to grasp that a stressed-out plant, which just underwent a drought-mimicking sudden loss of roots, needs water to help those roots recover.
It is true that saguaros and most succulents can survive on internally stored water for quite some time while they try to replace those missing roots, which is the only reason we can bare root them so harshly in the first place. Most woody and leafy trees and shrubs treated this way would be dead within a few hours or a couple of days, because catastrophic root loss paired with lack of internal succulence and water storage means fatal dehydration within a few days at most. This is why we don’t bare root most trees (only specialized treatments in certain nursery settings is permissible in narrow circumstances) – it is deadly. But just because succulents are more tolerant of root loss and dehydration doesn’t mean their boundaries are infinite. This is why we should still water new cactus transplants and continue doing so for as long as it takes for them to regrow the roots and fully recover.
How long that watering aid is required depends upon a variety of factors. How many roots did the plants start with? How dry has the weather been? What time of year is it? How healthy was the saguaro to begin with, and how large or old was it? What are the soil conditions – well drained or sandy or rocky or clay? Are there nearby water sources to help aid the growth, such as other irrigated plants? Are you observing severe dehydration in the plants, a thinning of the stems and shriveling of the ribs, or are they looking fat and hydrated? Is there new growth evident? All of these are clues that can help indicate whether watering is still needed.
As a general rule I wouldn’t consider a mature saguaro, with arms or even tall spears (12 to 16 feet) to be out of the woods with supplemental water until 3 to 4 years have passed. You water more in summer than in winter, with spring and fall in between. If the winter or summer monsoon has been generous with rain, you can water less for a few weeks or months. If the summer monsoon has been absent, like it was in almost all of AZ in 2020, then definitely water!
As for quantities, this varies with soil and weather and time of year as noted, but a good rule of thumb would be a minimum of 20-30 gallons at a time, once every 2 to 4 weeks, with more of it concentrated towards summer heat than winter chill. (Unless winter is very dry, which the upcoming winter of 2020-2021 may be.) If your soil is very sandy, more watering won’t hurt. If it’s denser silt or clay, less often is maybe appropriate. Rocky slopes don’t retain water as well as flatter areas do. The goal is a fairly thorough soaking every few weeks and then allowing some drying – but not bone dryness – in between waterings, which allows for a good balance of even moisture plus oxygenation.
Again you need not be perfect about this, but totally eliminating water is a terrible idea. What I have seen is that many cactus movers recommend no watering for 6 months or even a year. Why the hell not? I know they want to avoid “overwatering” but the end result is that already-stressed, suffering plants with a fraction of their normal roots are now being forced to dip into their irreplaceable internal water reserves, which are also finite, in order to survive in desperation. For god’s sake, help them out and water! This is the only way that they can grow some new roots and absorb new moisture so they can photosynthesize and make the needed foods like sugars, starches, and proteins that form new root tissues. Get them out of the death spiral!
Overwatering should be thought of as a chronic condition spanning weeks or months, not a one-time deal.Here’s an analogy: If you eat a huge meal on Thanksgiving, several times more calories than you would eat in a normal day, you are not going to gain 50 lbs from that. You won’t even gain 5 pounds. But if you eat an extra 500 calories a day that you do not burn off and which end up depositing as body fat, over the course of a year you can gain 50 lbs. Overwatering that results in root death and rot is like overeating that results in weight gain – it occurs over time, not once. And just as you need daily food for basic life maintenance, so newly transplanted saguaros also require regular watering (again once every 2 to 4 weeks, just fairly thorough when you do it) for basic life maintenance too – and it’s even more important when they’ve lost so many roots.
Alas the misconception among many saguaro transplanters is that offering any water whatsoever is going to result in rotting. I don’t know if this is what Roadrunner Cactus told you, but it is not uncommon advice, even if it’s grievously mistaken. Ironically, if they didn’t bother to preserve more roots, then the plants do become more rot prone – but it’s not because of the watering. Instead it is because you shouldn’t have chopped all the roots down to mere stumps and stressed the plants to within an inch of their lives!
One more issue with excessive root removal on saguaros is the fact that they are often plugged into holes that are far too deep for normal health, a thing I mentioned a bit without discussion earlier. There are two problems with this. The first is that burying 2 or 3 feet of trunk is definitely not normal for saguaros, and many of them develop trunk rot simply because of this fact alone. (Leading to my original article on bacterial necrosis, which has killed four of your plants already.) If they had more roots, they would be more stable and not require deep burial. Any unstable larger plants should be braced for a year or two while new roots grow to anchor the plants. My experience is that saguaros can pretty easily tolerate about 6 inches to 8 inches of trunk burial without a big threat of rotting, and maybe up to 12 inches; but beyond that, you’re pushing the envelope.
The other thing with deep burial is that if the root base is jammed 2 or 3 feet down into the soil, now the plants have major trouble redeveloping the shallow and surface-level lateral roots they require for normal water absorption. Additionally, the main portion of the roots is now unnaturally deep, located well below the ability of most desert rainfalls to penetrate. In most of Arizona’s Sonoran Desert, the average annual rainfall is only 6 to 10 inches, including most of metro Phoenix and Tucson. (Not sure where you live.) The majority of rains will be less than enough to soak the soil downwards 2 to 3 feet deep, and as a result these deeply planted saguaros experience consistent drought, which also hampers their recovery. Deeply planted saguaros will always require supplemental artificial watering that reaches this unnatural subterranean depth in order to recover as a result of this improper root placement. So this is yet another reason why movers should preserve the roots and not cut everything down to nubs. It’s better to plant saguaros with a decent fraction of their natural roots and make sure they are at a normal, somewhat natural, semi-shallow level. With supplemental initial watering as well for 2-3 years, of course.
By the way, whatever expert told you that it was planted too shallowly and that exposed the plant base to rot doesn’t know what they are taking about. There’s no such thing. Wild saguaros grow at their normal depth with mostly exposed trunks leading down to the lateral roots within a few inches, and they almost all survive fine for decades without rotting. It is too-deep planting that causes most rotting, although often that’s in conjunction with root loss and lack of watering as described. Not just one factor in other words.
This is a long and complicated answer to your situation. In fact I am now planning to take all this that I just wrote and edit and modify it to form the basis of a companion “how to transplant saguaros correctly” article to the necrosis one. I won’t identify you in it, but this information needs to be out there and anyone who moves saguaros for a living should read it and understand the logic being applied. I do know that some saguaro movers are adopting these practices I have laid out, but some do not, and the result is death and suffering from both the plants and their owners who are watching their expensive, cherished investments die.
As to what you should do, it is pretty likely that the 4th saguaro which has the rot but hasn’t died yet will just continue its decline and ultimately perish. You can treat and see if it helps but I wouldn’t necessarily expect much optimism. If your 5th one is still hanging in there, make sure it’s getting occasional watering, and if you were told to not water at all and it’s been many months or more since it got anything, then by all means go out there and water it today! We got no monsoonal aid this summer in most areas, so if you didn’t water it, it’s now in very deprived shape. I hope it won’t be too late. If it does rot you can just let the skeletal portion stand behind and salvage that, although it means you’ll have to ignore or tolerate a rather smelly, decaying mess for a few weeks while it disintegrates.
Thanks for reading and I hope this helps. I’m going to post the comment and then copy the text into a new blog post since I spent so much time on it and I feel the information is important to have available online.
Jan, you are a blessing. The only source with so many ANSWERS that make SENSE after my suffering years of countless misdirection and unanswered questions from “experts.”
I’m happy to give any further details to help you in your next post about this. I also have several photos from each saguaro slowly dying from necrosis after being planted and realize the value might help others from making the same mistake I did.
I’m realizing these transplant companies (seems several I am being told) damage the cactus upon transplant and never tell the customers who are paying thousands that survival rate is slim to nil… I thought it was odd that Frenchie seems to be close partners with this company, and well, if Roadrunner Cactus has such a proven bad rep (at least in my case) for planting 4 out of 5 saguaros with a death rate between 1-4 years after transplant is pretty good odds poor transplanting practices helps Frenchie’s business model as “The Cactus Doctor” Helping confused and disappointed ignorant customers like me try to salvage their sick Saguaro.
It’s so upsetting because it’s feeling to me that since no homeowner knows a Saguaro can be so heavily injured during transport, with shallow-roots
(I watched all of mine be planted, I was right there at the site)…
…I only saw about 1.5’ of roots attached… and perhaps you can speak to the use of sulfur? Another saguaro person told me upon transplanting, these companies not only cut the roots too short, but they don’t “clean them with sulfur” before planting, which opens them up to infection. Is this true?
(Also for information sake, I’m in Phoenix).
And yes, these cactuses were planted in April/May… 2 of them were 15 Foot Spears (armless), and those were the first ones that died immediately our of the 5 total. (The other 3 being 20-25 feet tall, one with 13 arms which suffered a slow demise thereafter in the same way).
And given your wonderful explanation of timing for proper planting, it seems the timing was right in the wake of 0 protection of a hot, stressful summer. (thank you for explaining and addressing all of this on such valuable detail.)
Also, yes, Roadrunner Cactus gave me careful instruction to water only initially in the first month, once after the initial planting, and again 2 weeks later and then leave the plant alone, reassuring me they are “very durable, and will start growing its new root system because they love the summer.”
Reading back your thorough response, now their instruction sounds lubricious. And despite the company or Frenchie (who made multiple trips to my house) never once mentioned the importance of shade cloth to reduce plant stress after a transplant.)
I’m facing now watching this magnificent giant’s slow demise, and (it does have 3 bud like arms, under 12” long) that have grown on the east side… I’m thinking of harvesting and trying to plant them to save what I can. I know to be careful to catch in a net and not let the arm bud crash to the ground which would just cause fast bruising (this happened at transplant before with this company with 2 saguaros, learning the hard way again.)
Can you give me tips for saving the bud arm “kids?” And growing them? I know I need to act fast as I know this infection has overcome the root system almost completely around the whole base as of now. I had it braced so hopefully it does not destroy my fence. (Sigh) Thank You for being there and for having this amazing blog. I’m literally going to save all that you’ve typed here in my saguaro notes. ❤️🙏 Blessings To You
I appreciate your expansive knowledge of the saguaro and I’m grateful to have found your blog, thank you. I can’t, however, find anything relevant to my question anywhere I have looked online. Perhaps you could try to help us. We live in NE Tucson and have a couple of dozen saguaro spread over about an acre. Most of the specimens (natural, no transplants) are showing a deep red color creeping up the trunk from the bottom. Almost all of the color is on the South side of the trunks on the affected plants. The only difference I see in the unaffected plant’s situation is that the caliche underneath may be further down. Full sun exposure or partial shade does not appear to be a factor. I see no evidence of necrosis and the affected plants seem otherwise healthy. I have noticed this color change since late summer. Any ideas, please? Thanks, Mark
It is not uncommon for cacti, not just saguaros but many other species, to develop reddish or purplish colored pigments when under stress, especially from sun, drought, or cold. The pigments are designed to block UV rays from damaging the plants’ epidermal cells when they are in a reduced metabolic state, such as the factors listed above. It’s similar to the melanin we produce in our skin in terms of protective anti-UV functionality. Some cacti such as Santa Rita prickly pears are very purple, even in their normal healthy state, while many other cacti (and succulents such as agaves and more as well) are much less purple by nature and only develop it under stress. Some individuals vary too, just like human skin color varies.
Anyway it’s nothing harmful and while some saguaros will exhibit an increased tendency to adopt this pigmentation compared to a neighbor nearby in nearly identical conditions, rest assured that there’s nothing to worry about. 2020 is an extremely dry year (and this may continue into 2021 unfortunately) and saguaros are likely to show more purpling than normal for the time being. Look on other cacti and you’ll probably see it on different species in some cases as well.
Thank you, we are grateful for your help!
Thank you. It was an amazing ride reading your expertise in the matter. I’
Thank you, glad it was helpful.
Thank you for this information. I have a beautiful large Saguaro in my backyard. A large arm fell off suddenly and there is the smelly black liquid that you describe coming from the inside of the cactus where it broke off. I tried to find information on this for days to see if there was any way to save it. However, after reading this and reviewing the pictures, I am convinced it has an infection that is not treatable due to the location being so deep inside the trunk. It was truly like a cancer that I could not see as there were no wounds or black liquid on the outside of the cactus. It was green, growing and flowering. Your article has set my mind at ease that I am making the right choice to remove the Saguaro before it can cause damage or harm from falling or spreading this disease to the other nearby cacti in my yard. I cannot thank you enough for taking the time to post this.
I’m glad that the information helped bring clarity to your decision making process. Sorry about the loss of your saguaro, but it does indeed happen and as I have said, nothing lives forever anyway even if some things live for far longer than humans do. Sometimes it’s best to learn to philosophically accept these things and make decisions to move on, while considering the health of nearby plants as well. I understand the anguish that these situations can bring however, but at least understanding that sometimes things happen that are beyond your control, such as the sudden appearance of the bacterial rot and not even knowing it was happening until it was too late to treat. It’s not your fault, and I hope that knowing this might provide some relief.
I have a situation I haven’t seen discussed here. I have a 4 Ft Saguaro- was 6 Ft,- that I have grown up from a 2 inch seedling purchased from the Arizona Desert Museum. It has lived all its’ life in the San Francisco Bay area, in pots, until i had a suitable location in-ground to plant it 5 years ago.. It was really happy, because it grew from 2 ft tall to 6 feet. A year ago, it developed a ‘rot’ about a foot down from the top, that eventually spread all the way around the circumference. There was no dripping of sap.
We decided to try to save it and cut it straight across about a foot lower and discarded the top. I did not know to spray it. The interior has shrunk down around the ribs, but there’s been no more sign of rot. I was concerned about rainwater pooling in the cavity, so we made a cap for it through the winter.
About November, it started to grow a ‘nubbin’ at the top edge, and it now looks like there may be 2 more, that I presume will grow into arms.
The first one is now about 4 inches in diameter and is starting to elongate.
My question is, how can I treat the 3 inch deep cavity in the center, between the ribs. I’d like to do more than putting a ‘hat’ on it through the winter.
If you make a careful incision between what sound like the new arms (side budding stems that are replacing the original, now missing central head) with a sharp, clean and sterile instrument like a saw or knife you can cut a “drainage channel”. Doing that will allow rainwater to drain off to the side and into the ground, rather than pooling in the central cavity that remained after it shrank away a bit. You probably only need to cut one such channel and only a few inches deep into the stem below, kind of at an angle. The goal is just to stop water from pooling up top and allowing it to drain down. Summer would be a good time to do this because there shouldn’t be any rain in your area anyway, and it will enable to saguaro to callus over the cut with scar tissue that should turn dry and scabby in the summer sun and drier air. The cut can be a groove or a small v-shaped channel. Mind you that a thin groove can close up with scar tissue and then you won’t solve the problem, so maybe make it a bit wider and slightly v-shaped as stated. Eventually the new growth points will enlarge and sort of crowd the entire top out anyway and it probably won’t catch rainwater by then anyway, but for now try the drainage cut.
Hi Jan, found this website too late to save a twenty foot plus saguaro that had several arms from developing this disease. We were going to have the cactus doctor company come out and skeletonize the cactus because Mr. LeBlanc said that the rot was too far along to save the saguaro. Unfortunately a week before we were going to do this, the cactus fell over. How far and extensive are the roots of a saguaro, is it hard to do the job thoroughly, and do I treat the soil with the rubbing alcohol or bleach solution? Thinking about planting an ocotillo in the same area. How far away should we plant it?
Sorry I did not see this comment until well after you submitted it, Cliff. Indeed sometimes cacti are simply too far gone to save and removal or letting it decay is the only remaining option. Many captive saguaros don’t have roots as extensive as wild ones do because of the root loss they experienced when originally transplanted, or due to not needing to reach as far for water as wild plants do living on rainfall alone. But I wouldn’t bother with trying to dig out the roots anyway, just let them decay underground in place.
If you’re not replacing the saguaro with another cactus species you can probably not treat the soil and the new inhabitant of the space will likely be fine. Ocotillos are not cacti and aren’t subject to Erwinia cacticida bacterial necrosis, although they can of course die from different non-cactus pathogens especially when under bare root transplanting stress. If you just plant the ocotillo 4 to 6 feet away from the original position of the saguaro trunk, that should be okay without much further treatment necessary. Assuming you buy a healthy ocotillo or a potted one that definitely has roots and leaves, then there should be no problems. If you buy something bare root and leafless, especially those poor abused plants sold in dry bins at Home Depot etc, which have no more than a few inches of root stump left, well those are a very poor prospect and I would not waste my money on them. Those are 75% likely to be dead on arrival. Buy a live, leafy ocotillo, even if it’s smaller, and it should be fine and establish and grow quickly over the next few years. Agaves are also decent choices, and they are not cacti either.
Thanks for the article! I have a saguaro and am growing it as a houseplant. Three weeks ago, I noticed black spots along some of the spines. I’ve been treating it with a fungicide, but I might try alcohol. The cactus is 20 years old.
Thanks for the great article. I live just south of Saguaro Nat’l Park East. We had a tall, many armed, iconic saguaro start falling apart from necrosis. The base has lost its flesh outside the ribs, but there are still two healthy arms. I noticed a saguaro near the park, also with no flesh outside the ribs at the base, and it has clearly healthy arms above. Any chance it could survive as is if the core isn’t infected? Or is that an unrealistic wish? Thanks!
I suppose it is possible, although time is not on its side on the long run. (Is it for any of us?) The saguaro you saw in the wild at the park might have been damaged via other means, not by necrotic rot – perhaps it was browsing by rodents or ungulates for example? If the trunk was down to the ribs and the damage was between ground level and about 2 feet high or so, then I’d blame rabbits and jackrabbits for having gnawed off the flesh, and rot wasn’t likely to be the cause. While saguaros damaged by hungry rabbits are weaker than intact ones, they also can survive for decades and even reach a semblance of normal maturity. In your case, where you know it was rot and trunk damage is already extensive, I’d more or less just expect final decay to occur within the next few months to year and full death to commence. If not, then enjoy the reprieve for as long as it lasts; but I would expect otherwise….
Jan – thank you for the extensive information! I moved to Arizona three years ago and the house we bought has a very large (taller than the house) saguaro in the front. The house is now 23 years old, so I am guessing it was not massive when transplanted. However, the previous owners did not take care of any of the plants and the saguaro had a black bottom (overwatering). I had a tree service prop it as it was leaning, but now see grey where the carpet is on the tree. They are coming out to inspect, but I fear the worst. Will the bacteria ever leave the ground? Is there a timeframe for when you could safely plant another cactus in the same spot? I have been thinking of not putting another cactus there anyway, but I am curious.
I am also wondering where you are located and if you care for cactus as a profession. I would love to hire you – you are so knowledgeable!
I’m going to copy and paste a reply to another comment recently received, rather than retype it, Robin. But more specifically to your case, the Erwinia bacteria is present in the ecosystem at large in most of Arizona, and it usually doesn’t damage or kill healthy, non-stressed plants. There’s no real way to fully eliminate it from the ecosystem. That said, I would avoid planting another cactus of any sort in a highly contaminated spot, such as one with soil soaked by rotting cactus juice. That’s just asking for trouble actually. Know that many succulents are not cacti – ocotillos, yuccas, and agaves are all non-cactus succulents, and they aren’t prone to Erwinia attack. But those plants can still succumb to other diseases that look similar in appearance (and outcome) although they’d be better choices for panting where a saguaro died. Don’t plant now in August! Wait until summer is over and plant in October, regardless of whatever it is you are replacing it with.
“While you can certainly try a last-minute emergency intervention, based upon your description the rot has progressed very far and sadly your plant is likely to be dead within the next 2-3 months or so. The extreme summer heat in all of July and most of August 2023 has done in probably thousands of saguaros, especially in urban regions with a pronounced heat island effect. That heat island phenomenon manifests in two ways – one is of course during daytime highs (often over 110 F) and the other is during high nighttime lows (where temps fail to drop much below 90 F before sunrise.)
These hot nocturnal temps paired with a long duration without breaks in a year like 2023 when the monsoon season has been poor in most regions are what stress the plants out to the point where they become vulnerable to infection spreading rapidly through the vascular system and not showing up until it’s too late. It’s also hard to actually prevent, because the best preventative (cooling down both day and especially at night) isn’t happening.
Climate change is likely to continue to make extreme summer heat waves more likely, and all sorts of plants – not just saguaros, but agaves, barrels, yuccas, prickly pears, and much more – are prone to this type of metabolic heat stress and death related to it. Shade cloth can help stave off some of the heat stress by reducing direct solar radiation hitting the stems and leaves of your succulents, but without some nighttime cooling to the low 80s or below F, it’s perhaps just a matter of time regardless. The plants cannot function normally or conduct the photosynthesis they need to to stay alive when it’s so hot for so long. Watering and shading can help as I say, but only so much, and once extensive necrosis sets in it’s likely that the saguaro etc will die anyway. 🙁”
We returned from a one week vacation and noticed one side of our large saguaro has turned black.
Upon further inspection, 1/3 to 1/2 of the large trunk is soft and spongy. The black skin of the cactus goes up over 10 feet with various smaller splits with small amounts of black fluid emitting.
I’m sure we have the bacteria necrosis. I plan to try and save the cactus very soon by cutting away all the flesh that is affected. However, I fear it is a lot to remove and may be too late.
If any anyone has had any success of dealing with this bacteria, I would appreciate any information you could pass along.
While you can certainly try a last-minute emergency intervention, based upon your description the rot has progressed very far and sadly your plant is likely to be dead within the next 2-3 months or so. The extreme summer heat in all of July and most of August 2023 has done in probably thousands of saguaros, especially in urban regions with a pronounced heat island effect. That heat island phenomenon manifests in two ways – one is of course during daytime highs (often over 110 F) and the other is during high nighttime lows (where temps fail to drop much below 90 F before sunrise.)
These hot nocturnal temps paired with a long duration without breaks in a year like 2023 when the monsoon season has been poor in most regions are what stress the plants out to the point where they become vulnerable to infection spreading rapidly through the vascular system and not showing up until it’s too late. It’s also hard to actually prevent, because the best preventative (cooling down both day and especially at night) isn’t happening.
Climate change is likely to continue to make extreme summer heat waves more likely, and all sorts of plants – not just saguaros, but agaves, barrels, yuccas, prickly pears, and much more – are prone to this type of metabolic heat stress and death related to it. Shade cloth can help stave off some of the heat stress by reducing direct solar radiation hitting the stems and leaves of your succulents, but without some nighttime cooling to the low 80s or below F, it’s perhaps just a matter of time regardless. The plants cannot function normally or conduct the photosynthesis they need to to stay alive when it’s so hot for so long. Watering and shading can help as I say, but only so much, and once extensive necrosis sets in it’s likely that the saguaro etc will die anyway. 🙁
Thank you very much Jan for your timely response. I appreciate all your efforts.
Best regards, and God bless.
Jan – Thanks for the info! I have a large Saguaro Cactus which has black rot and maybe too far gone. But I’d like to preserve one or more of the small arms. So, I can regrow at least part of that Saguaro in or near it current location. Bottom line: Can a new cactus be grown from one of the old cactus’s arms?
Saguaro arms do not root very well and the likelihood of them failing to recover is very high, probably over 90%. Unlike many (but not all) other cacti, saguaros don’t root easily from cuttings which is part of why they are sort of expensive, since they need to be sown from seed and that’s time consuming. You can try it, but not too put too fine a point on it, I’d expect it to not work. Entire small arms of under 3 to 4 feet long are the best bet. Longer arms, arms that have already begun rotting themselves, and central stem or tip cuttings are not worth attempting in my estimation….