A pink larkspur (Delphinium ajacis) grows in my gardens, one of a number sown from a packet of mixed colors that would also include blue, purple, and white. Unfortunately, most of the seeds did not germinate, and most of the few that did are undersized in early May 2019.

One plant I would enjoy growing more of is larkspur (Delphinium ajacis) but their life cycle isn’t quite right for desert culture. Most of the annual plants that do well here in Arizona will germinate in autumn of the year before, grow slowly but steadily over winter, bolt into bloom in early to middle spring, and complete their life cycles before it gets too hot and dry again. It sounds like a typical annual pattern, similar to the path followed by warm season annuals, right?

Another pink larkspur grows next to a Ferocactus pilosus. This one is much smaller, blooming at only around 8 inches tall. The other flowers are Moroccan toadflax (Linaria maroccana) which did do very well in my gardens, although these are the few straggling blooms that remain after most have gone to seed already.

A few days after I made this original post, a purple larkspur managed to open up next to yet another pink one in a different spot. So I am adding it to my blog just because every other plant in it was pink or red. 😉

Well close, but not entirely. There is a group of garden annuals that almost, but do not quite, follow this pattern. Larkspur, Shirley poppies, bachelor’s buttons, Calendula, cosmos, flax, and others fall into this category. They won’t germinate in warm fall weather or in cold winter temps, but will emerge in cooler early spring conditions. They tolerate some frosty weather and survive the early springtime chill just fine as small seedlings, but they “waste” a lot of growing time in a rainy desert winter or early spring, sitting idly and waiting for warmer temps to activate, rather than actually growing like the desert-adapted species do. Unfortunately, this late start means they are usually unable to complete their life cycles properly before things get pretty warm and dry again in May and June, which would otherwise be prime bloom times for these plants.

Bachelor’s buttons or cornflowers (Centaurea cyanus) are another garden plant that is marginal for the Sonoran Desert. These were also part of a mixed color packet, and while the classical color is blue, for some reason these pink individuals were the ones that managed to flower this spring.

As a result of this hard-wired timing, I see only a few plants such as this pink larkspur which are able to get to normal size before they are taken down in warm (and sometimes outright hot), dry spring Arizona weather. The native desert annuals are either finalizing seed production right now, or already completed it weeks ago. Meanwhile the more temperate-climate larkspurs, Shirley poppies, and calendulas I sowed last fall are only now thinking about blooming. And sadly, it’s really getting quite late for them. They are definitely showing signs of heat and drought stress, and it is barely even May!

Shirley poppies are a horticultural derivative of the common corn poppy or Flanders poppy (Papaver rhoeas) that come in a wider array of colors than the usual bright scarlet. They too have color variances. Note how this plant is producing just a couple of flowers and the leaves are already aging and drying in the warmth of late spring. They’re simply running out of time and water, even though I have aided them when rainfall was insufficient.

That’s what separates true desert annual wildflowers from the beloved but cultivated “garden wildflowers” that thrive over most of the rest of the country. The rest of North America receives a later onset of summer heat, not to mention much more rainfall. Those are factors that enable widespread success of these cultivated garden annuals across most temperate climates. Here in the desert southwest, the margins of success are quite thin for these otherwise reliable standby garden annuals. And despite the successful flowering of these few individual larkspur, poppies, and cornflowers, I am watching numerous other undersized seedlings struggling to do any blooming at all before they dry out and die early deaths.

One more plant that performed marginally for me is red flax (Linum grandiflorum rubrum). These few flowers are fading because I didn’t catch them sooner when they looked fresher, but the basic pattern of rushed maturity befalls this species in the same way as the others above. The other flowers are toadflax again, which should be featured in an entirely separate post simply because those absolutely ARE successful in the Sonoran Desert, since they follow the fall-germinating, winter-growing, spring-blooming pattern that native annuals also do.

This is what garden experimentation is about however: Seeing what works and why, as well as how the interplay of weather, climate, genetics, and built-in life cycles operate. So anyone living in a warm desert climate who might be thinking about buying one of those commercially sold “wildflower seed mixes”, know the species in it, and why they might not really be suitable for us here in the deserts. For most gardeners it’s probably better to go with native seed mixes (or desert annuals from analogous climates that translate over well, like African daisies and Moroccan toadflax) that get an early start the year before, survive all winter, and grow and bloom in early springtime.

That all said, I will probably spend a few dollars a year on sowing seeds of a handful of species like the ones covered in this post, ones that do manage to put forth a few flowers, even though by temperate standards they are mostly failures. It’s a bit irrational, I know. But gardening isn’t always about rationality only, now, is it?