Jatrophe are medium or small shrubs, originating in South America, now widespread also in Asia and Africa. The species are about a dozen, all very similar: the foliage is large, dark green, palmate, carried by long arched petioles; the flowers are gathered in small umbels, of small size, but of a bright and brilliant color, orange or red. The plant has a short stem, poorly branched, at the apex of the branches sprout the long petioles that carry the leaves; some species have a caudex, or a swollen stem, which keeps the water in dry periods. These plants are grown by us as houseplants, especially for the showy and pleasant foliage; the species cultivated in the apartment are generally those of reduced dimensions, which remain below the meter of height approximately.
These plants have spread into the apartment thanks to the great ease of cultivation and their great capacity for adaptation; their root system is contained, and therefore allows to place the jatrophe in very small containers, without fearing for the health of the whole plant. We therefore choose a vase that is not too large, also because with a not excessive amount of earth it seems that these plants tend to develop better; let's place them in a well-lit place, even directly exposed to sunlight, we avoid the dark areas, also because we will hardly see the flowers of a jatropa grown in an area not properly lit. The jatrophe are used to living in places with a climate that is not too rainy and hot, therefore they cannot live outdoors in Italy, where they are kept in the apartment for the entire cold season; during the hottest months we can therefore place them outdoors, so that they enjoy a more ventilated climate than the one in the house.
These plants need not too regular watering, it's enough to moisten the soil when it is dry; they endure the drought without problems, even very prolonged.
When in winter the climate is very dry and the hours of insolation decrease the jatrophe tend to lose the foliage, or to maintain a few leaves (in the very small specimens it often happens that the jatrophe in winter have a single stalk, with a leaf at the top or some flowers); don't worry if this happens, let's just avoid watering the plant until the days get longer, in January-February; when we start watering again, the plant will start producing new lush foliage.
To cultivate them to the fullest
Even if the jatrophe vase is small we try to fill it with the most suitable soil; we prepare a very porous and draining substratum, mixing a part of universal soil with half a piece of sand and a little crushed pumice stone. Let us remember that periodically it is good to repot the plants grown at home, changing all the soil contained in the vase. From March to September we supply fertilizer for flowering plants, every 12-15 days, mixed with the water used for watering. We avoid exposing ours jatropha in the cold, but try to keep it at temperatures above 15 ° C; if we put it at home we avoid places subject to drafts or near windows or heat sources.
Jatropa - Jatropha: Some curiosities
For us it is a houseplant, but in places of origin the jatrophe, especially those belonging to the Curcas species, are grown for large oilseeds; with the oil of jatropha an excellent biodiesel is produced. These plants have also been cultivated in Africa for centuries, where, being poisonous to animals, they are used as fences in cultivated fields. In much of the planet the cultivation of jatropa is spreading to exploit its oil; For some years, we have been trying to grow jatropa curcas also in Italy, in Sardinia.