Jatropha

The genus jatropha (Jatropha) comprises about 175 species of plants found in the tropics and subtropics of the Old and New Worlds. These are herbs, shrubs and trees of the spurge family (Euphorbiaceae). Some of them are cultivated as ornamental plants in tropical gardens and as houseplants. The name Jatropha comes from the Greek words Jatrys - doctor, and tropha - food, and refers to the medicinal properties of some representatives of this genus (for example, Jatropha curcas).

The native range of jatropha is Central America, but today it grows in many tropical and subtropical regions, including India, Africa and North America. From the Caribbean basin jatropha was spread as a valuable hedge plant in Africa and Asia by Portuguese traders. Like many other members of the spurge family, jatropha contains compounds that are highly toxic.

Jatropha multifida, native to Mexico, Central America and Brazil, grows as a small shrub. In nature it reaches a height of 2-3 meters and is covered with attractive leaves (up to 30 cm in diameter), divided into 7–11 lobes.

The leaves of Jatropha multifida are dark green with a slight bluish tint and a lighter center. Over time they fall, leaving the lower part of the stem exposed. Young plants resemble a small palm and look very decorative.

The bright coral-red flowers of Jatropha multifida are gathered in umbel-like inflorescences raised above the leaves on long "stalks" that emerge from the growing point. In the tropics jatropha blooms almost year-round, especially intensely during the hot months. After flowering it produces yellow three-sided fruits about 2.5 cm long, whose white oily pulp contains three "nuts." Seeds are brown, oval, about 1 cm long. In the wild jatropha often self-seeds and can therefore be a "weed."

All parts of this plant are very toxic. When the tissues are damaged, jatropha exudes a copious translucent sap that can irritate sensitive skin.

Jatropha multifida prefers full sun or light partial shade. With optimal lighting the plant looks like a small palm with a canopy of leaves. Lack of light leads to elongation of internodes and a less decorative appearance. Pruning the top of jatropha induces branching. This operation is best performed in spring or summer, when maximum light is available.

In nature Jatropha multifida grows on various soil types but prefers a loose, well-drained potting mix. Drainage is essential. Watering is regular, but the plant can tolerate short dry spells, shedding some leaves. In winter watering should be reduced, and the little tree is moved closer to the light, to a cool place, away from central heating radiators. Jatropha may shed some lower leaves in winter; this is normal.

Jatropha is propagated by cuttings in spring, as well as by seeds. Seeds usually germinate within a week; if they have not sprouted by then, they are slightly nicked.

Jatropha podagrica from Central America is an unusual and still relatively rarely grown plant for gardeners. Its swollen stem base and large leaves immediately attract attention. Completing this exotic picture are umbels of bright red flowers rising above the leaves.

The lobed leaves of Jatropha podagrica are rounded and reach 15–18 cm in diameter. Their color depends on age: young leaves are dark green and glossy; as they grow they lighten and then, when reaching their usual "adult" size, darken and become matte. The underside of the leaf and the petiole are pale and covered with a glaucous bloom.

The flower cluster of Jatropha podagrica is a compound umbel and emerges from the growing point. At first these are modest buds, and only a few of the largest are visible. At first they develop slowly; upon reaching the leaf level their growth accelerates and the buds begin to color. Then small coral-red flowers up to 1 cm in diameter open. Jatropha flowers are scentless. Both male and female flowers are located on the same umbel. Male flowers usually last one day, but new ones continuously open to replace them — the flowering of one umbel continues for several weeks. In natural conditions Jatropha podagrica blooms throughout the warm season.

This plant is undemanding, and if simple rules are followed, it can be successfully grown by novice gardeners.

Jatropha loves bright light with direct sun, but at midday light shading is still necessary. In full sun the leaves of jatropha grow smaller with short petioles, making the plant more compact.

The potting mix for planting and repotting jatropha should be water- and air-permeable, with mandatory drainage. The plant develops a powerful root system and quickly occupies the flower pot.

Watering is regular, as the top layer of soil dries. Jatropha podagrica easily tolerates drought and strongly dislikes waterlogging. In summer it is difficult to overwater a mature jatropha — its large leaves transpire a lot of moisture, and the plant often needs daily watering. With insufficient moisture the leaves wilt, but this does not cause harm — on the contrary, it is necessary to make a real effort to subject jatropha to a true drought for its leaves to begin yellowing and falling. However, flowers respond negatively to insufficient watering and may drop.

In winter watering of Jatropha podagrica is reduced to a minimum or almost stopped, and the plant is moved to a cool place (usually a windowsill located away from central heating radiators). In autumn its leaves may fall partially or completely.

Jatropha podagrica is propagated by seeds, which germinate easily within 1–2 weeks. Many sources indicate that its seeds should be sown as soon as possible because they quickly lose viability. Seedlings of Jatropha podagrica develop rapidly, and within a few months they become like adult plants. Initially the leaves are rounded, then their edges become wavy; lobed leaves appear on the plant in the second year of life.

Location: a bright and warm place without direct sunlight. From March to September the temperature 20–25 °C, in winter 10–15 °C.

Light: bright light.

Watering: moderate, only after the top layer of soil has dried. In winter, after leaf drop and until new shoots appear, watering is stopped.

Air humidity: moderate.

Care: fertilize from spring to autumn once every three weeks with cactus fertilizers; at other times do not fertilize.

Propagation: by seeds (usually a flowering plant produces several seeds). Sow them in standard potting mix and keep in a warm bright place. Transplants are moved into individual pots (use a mixture of ordinary soil with added loam).

Repotting: every one to two years in spring or summer.

Possible problems: practically resistant to diseases and pest attacks.