by Bruce Brethauer
During a recent visit to the OSU Biological Sciences Greenhouse Facility, I noticed two great plants of Jatropha podagrica, both of which were mature, with well established caudexes. One of the plants had the remains of old flowers and a few fruits, and the other was producing a umbel of its vibrant red/orange blossoms. It caused me to reminisce about a plant which I had once grown some years ago, and to ask why I had ever allowed myself to part with it at one of the Society's annual sales. This is a pretty fantastic plant, producing a good sized caudex in a relatively short time; the rough, peeling bark adds interest, and very large, deep green fig-leafed foliage and the brilliantly colored flowers produced over much of its growing season makes this species a popular garden plant in regions with mild climates, as well as a popular plant with succulent and bonsai enthusiasts.
The Jatrophas are close relatives of the Euphorbias, and are widely distributed through tropical and sub-tropical regions worldwide. Approximately 170 species have been described. While the majority of species are native to the Old World, there are over 60 species which are native to the New World. Most species are shrub sized plants, with a few tree sized species. The majority of species are native to dry regions, or regions which are seasonally dry. A good number of species are popular plants, producing good sized caudexes, and colorful flowers over a long period. Many species produce unusually high levels of oils in their fruits, and some have been considered good candidates for bio-diesel fuels, and to provide industrial lubricants. Many years ago, the nuts of some species were used medicinally as a powerful laxative and cathartic, but due to the presence of toxic substances in their sap and seeds, these uses have been largely discontinued.
Jatropha podagrica is native to Panama and Guatemala, and probably inhabits regions which are seasonally dry. Plants typically grow as low shrubs (one of my sources indicates that plants grow to only about 20 inches in height - but I suspect that the ultimate height of plants in habitat may be in the range of 3 to 6 feet. The plants produce a thickened trunk early in their development - even plants which are just a few inches in height will exhibit its typical bottle-shaped trunk. The trunks eventually produce a rough and peeling bark. Many plants eventually produce a multi-branched trunk, but plants can be encouraged to branch earlier by pruning. The main branches also have a pachycaul appearance, which gives older plants the appearance of a miniature Baobab tree. The foliage is large (up to 12 inches across) and is lobed (typically with 3 or 5 lobes) and looks similar to an extra large fig leaf. The large size and deep green coloration of the foliage makes this a good plant for the tropical look on the patio, and this species and other jatrophas are frequently grown as garden plants in frost free regions where they can be grown as perennials; growers in other regions will need to grow these in pots and bring them indoors when temperatures approach freezing. The flowers are brightly colored - typically with coral to orange colored flowers, and are quite attractive. Although the individual florets are small (to just over 1/2 inch across) these are produced in good numbers on branched panicles, which are produced more or less continuously through the summer months. The flowers are also good nectar plants, and are known to attract many butterfly species which feed on its flowers.
When I grew my plant many years ago, I made many mistakes: I treated all of my succulents as if they were denizens of extremely arid deserts, and tended to underwater everything. I also tended to plant them in a medium which was mostly comprised of sharp builders sand to provide "perfect" drainage - not only was this overkill, but sand provides virtually no nutrients to the plant, so I was also starving may of my plants as well. Even when provided less than adequate growing conditions, my plant persisted, and even managed to produce a little growth, but it did not thrive. This plant does much better when using my basic guidelines for growing cacti and other succulents. Once again, I must emphasize that this plant grows best on the patio under very warm conditions, with lots of direct sun, and frequent watering (but not continually moist conditions), and the occasional application of a bloom-booster fertilizer. I have not had the opportunity to test a variety of growing mediums with this species, but I suspect that a medium containing a good percentage Moo Nure would probably give good results. Where this plant is happy, it will reward you with good growth, the production of large lobed leaves, a long succession of vibrant, butterfly-attracting flowers, and a steadily increasing caudex with lots of character, and interesting, textured and peeling bark. In winter, this plant will benefit from a cool and dry dormancy period - don't worry about foliage loss at this time, and don't expect it to continue flowering - maintain it at cooler temperatures and dry conditions (with an occasional light watering to prevent excessive root loss). As temperatures start to rise again in spring, water more frequently, and provide warmer temperatures - when temperatures outside permit, gradually acclimatize it to increased sunlight and temperatures and watch it grow.
While I do not know the cold tolerance of this species, I expect that it should not be subjected to sustained cold - I believe that it will tolerate brief exposure to near freezing conditions, and a well established plant may even tolerate a few degrees of frost, but it is always best to keep this plant protected from extreme cold snaps and extended cold.
I should stress that this is not a great plant for all circumstances - as with most members of the greater Euphorbia family, this species also produces a white latex in its sap which is both toxic and irritating. The seeds also contain toxins, and should not be ingested - so this may not be a good choice for households with pets and very young children.
While once a very popular and widely available plant - it has recently been less easy to locate (at least here in Ohio - perhaps where it can be grown outdoors year round, it may continue to be more widely available). Even in specialty mail order sources, it is not always available, however, it is frequently offered at the following mail order nurseries:
The Glasshouse Works