In 2010 I bought a small plant from the Huntington Botanical Gardens’ International Succulent Introductions (ISI) program, which works to bring rare and unusual succulent plant materials to the public. It was a seedling of Euphorbia stenoclada ssp stenoclada, grown from seed collected on Dec 14, 2007 south of Beheloka, Madagascar, and it was only about 4″ to 6″ tall. Now look at it 10 years later! It’s nearly 5 feet tall in a 5-gallon pot, and would be much taller if I could place it into the ground. Alas, as with most Madagascan plants, it’s not very frost hardy and therefore needs to be dragged indoors for the winter here in Arizona. I like it for its physical hostility and biochemical toxicity, which both mean that nothing eats it, and I have a lot of problems with herbivory in general so at least that aspect isn’t something I worry about.

My Euphorbia stenoclada is fairly green in aspect, with only hints of the silvery covering present in some plants. I am not sure if this is simple genetic variance, or whether it is due to the fact that it spends a good portion of its time indoors, and even when outside in summer it it on the shadier north side of my house. (Full sun tends to bring out whiteness in plants that are naturally covered in pale hairs, or wax layers, as the case may be. This one is waxy, which helps conserve water in droughts.)

The online photo below of Euphorbia stenoclada shows just how pale and silvery the stems and branch tips of this species can become. The image came from Wikimedia commons at the Spanish version of Wikipedia. (Image credited to: Euphorbia stenoclada, Playa del Inglés, De Schnucki – Trabajo propio, CC BY-SA 3.0)

This next photo of Euphorbia stenoclada was taken at a botanical garden in the Canary Islands. Again, note the beautiful shape and coloration the species achieves in a mild and frost-free oceanic climate. Photo taken from the English version of Wikipedia via the creative commons license. (Image credited to: ‘Jardin de Cactus’ Guatiza, Teguise, Lanzarote, Canary Islands, by Frank Vincentz, Wikimedia Commons, March 12, 2011.)

The next image comes from the French version of Wikipedia. This photo was taken on Europa Island, a small 11 square mile (28 square km) coral atoll located in the Mozambique Channel between the huge island of Madagascar and the country of Mozambique, on the southern African mainland. This and other photos of the species show adult plants in the wild often forming a sort of flat-topped crown that is visually similar to the acacias that Africa is so famous for from wildlife documentaries. However the acacias are usually turned into these flat-topped shapes by the browsing of large animals, most specifically elephants and giraffes, and trees not facing that pressure tend to have rounder crowns, like we usually expect many trees to appear. By contrast, both Madagascar and Europa Island lack elephants and giraffes, and as such the euphorbias are not forced into that shape, instead developing it naturally for whatever reason, independent of animal factors.

Whatever the cause, it’s a unique look and I wish that my domesticated potted specimen could grow outdoors here in Arizona in the ground, thus enabling it to achieve full size. But due mainly to frost, this is not possible for me, although it could probably grow outdoors in the lowest and hottest deserts of SW Arizona and SE California, as well as in moderate coastal climates such as Southern California and Hawaii. (Image credit: Wikipedia France, Par Pas d’auteur lisible par la machine identifié, by B. Navez, January 27, 2003.)

Lastly, just because I find these sorts of photos fascinating, here is an image (also from Wikipedia France) of Ile de Europa (Europa Island) where the above photo of E. stenoclada was taken. Taken from the NE corner of the island looking SW, you can see the central lagoon flanked by dark green mangroves and white sand beaches. An airstrip is seen as a white line to the right underneath the clouds. The island was uninhabited before 1820, when a single French family attempted to homestead it. Due to the lack of reliable fresh surface water and extreme isolation, they failed, as did several subsequent attempts. Now a nature reserve with a weather station and a French garrison on it, Ile de Europa is home to several important breeding seabird colonies and a couple of endemic insect species. Interestingly, a sizable plantation of sisal agaves (Agave sisalana) was established near the airstrip, and due to the drought-tolerant nature of these fibrous plants from Mexico they continue to survive to this day, unaided and isolated and potentially following their own evolutionary path, joining the native euphorbias as part of the scrubby flora of this tiny speck of land in the vast Indian Ocean.

(Photo credit: Wikipedia France, Roger KERJOUAN User:Galejade – en:Vue_aerienne_europa.jpg, January 7, 2007.)