Jatropha (2014)

PhotoBy Eric Driskill (November 2014)

Jatropha is a genus of plants in the spurge family, Euphorbiaceae. The name jatropha is derived from the Greek “iatros” (physician) and “tophe” (nutrition). Most species in the genus are native to tropical North, Central and South Americas, with about a third of the species native to tropical Africa and Madagascar. The genus has 170 species, with plants that are succulent plants, shrubs and trees. Most of the plants are considered shrubs, with a fewer number of species considered trees.

Jatropha flowers usually have dichotomous (forking into two equal branches) inflorescence. Most species are unisexual, with male and female flowers on different plants, although the genus does have examples of bisexual plants. As with many members of the Euphorbiaceae family, care should be taken with jatrophas, since the plants of this genus contain highly toxic compounds.

Jatropha curcas is currently considered one of the best candidates for future biodiesel production. An Internet search of the genus produces more results pertaining to this species and various biodiesel companies than to sites dedicated to succulent collectors.

Of the 170 species in the genus, a dozen or more particularly catch the eye of succulent hobbyists. Several examples include J. capensis, which is one of the most commonly grown species. Strict pinching and pruning will result not only in the trunk swelling but also encourages branching.

With so many of the species considered shrubs and trees, one that stands out as different is J. cathartica, which may also be offered as J. berlandieri. This plant forms a rather large underground caudex in time and is adorned with bluish leaves.

Jatropha cuneata is an exceptional candidate for bonsai, with its small leaves and swollen trunk. As with J. capensis, early and often pinching and pruning produce the nicest plants over time. Three other nice shrub species are J. cinera, J. gossypiifolia and J. mcvaughii.

A very nice species from Somalia is J. paradoxa. Like so many other plants from the Horn of Africa, this species looks like it is adapted to a harsh environment. The trunk is not as swollen as some other species, but the plants often branch liberally with a more horizontal habit. The plants are not often seen for sale and are quickly bought when made available.

J. podagrica is another species that is quite common in the succulent trade – and for good reason. The leaves can grow to be rather large, and like so many other species, it has bright red flowers. If left alone, the plants will grow to be rather tall and slender, and not appear very succulent at all.

This species is a very good example of how pruning can drastically change a plant’s appearance. When young, pinch the growing point, and over time, periodically pinch/cut the growing tip(s). You will be amazed at how this encourages the base to swell and over time produces a plant that has many branches with a swollen base.

Buy two, in fact, and grow one unmolested while pinching the other. See the difference for yourself in a few years. You will not only be amazed, but may also regret not pinching both!

PhotoThe last species I will mention is J. pelargonifolia, which hails from the South Arabian Peninsula and northeastern and eastern Africa. It has the best characteristics of all the Jatropha species rolled into one, but on a miniature scale. With some pruning, this plant will develop into a very small specimen with a swollen base, many branches and small leaves. J. pelargonifolia is very rarely offered and difficult to locate, if it ever makes it to your wish list. I have been trying to add this to my collection for years with no luck.

Overall, species in the Jatropha genus are not particularly difficult in cultivation. You should be successful when using a porous soil, and care should be used when watering during winter.