April 2012


Jatropha podagrica is native in South-America where it can grow into a large flowering shrub. It is now found in Africa and Asia as well, because this plant is propagated in nurseries and due to the springing of the seed when ripe the plant has escaped from the nurseries into the wild where it can establish itself. Due to the poisonous nature of the sap, there are few creatures that will attack it. Jatrophas belong to the Euphorbiaceae which can be seen by the seedpod that is divided into three sections, each containing one seed.
It is a plant that requires warmth; it will die if the temperature drops to 5°C for a prolonged period. The ideal temperature is at least 15°C. The plant is very easy to cultivate as long as the temperature is high enough, not requiring a specific type of soil; it can be grown in the full sun or above the central heating with little water. It can remain in this position all the year round, not requiring a colder period in winter. There is now a yellow form available besides the more usual orange. The yellow one will now come back true from seed which it did not do until a few years ago. If you cross the yellow with the orange, however, the orange will dominate and you could lose the yellow altogether.

Jatropha podagrica orange

Jatropha podagrica orange

Jatropha podagrica yellow

Jatropha podagrica yellow

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Because so may people liked the picture I put on my Facebook wall, I thought I’d write a bit more about Strophanthus speciosus. This plant belongs to the Apocynaceae, the same family the Adenium obesum (see previous post) belongs to. Most of the species in this family come from Africa, mainly from the tropical part, but one or two come from India, the Philippines or China. The S. speciosus comes from South-Africa. The name Strophanthus means twisted cord flower. Strophanthuses can be either climbers or shrubs.
The plants in cultivation are mainly grown from seed which will germinate in a couple of weeks in a temperature of about 20°C, but only if the seed is fresh, which you can achieve by hand-pollination. S. gerardii produces a tuber when grown from seed which I had not expected, as there is very little information in the literature about caudex Strophantuses. As far as I know that is the only caudex species, S. speciosus certainly does not have one.
They do not seem to be fussy about the soil type, but are not quick growers. They can be grown in either warm or cool conditions and are sometimes grown as container plants for moving outdoors in the summer. I have not tried it, but I doubt they can take frost. They do, however, have to grow to a fairly large size before they will flower.

Strophanthus speciosus