Pig nut is native to Tropical America. One of 150 Jatropha from tropical America with a few African species. This species was introduced to Africa centuries ago and is now naturalized in drier areas in many countries. It is a decorative plant frequently planted as a live fence around homesteads or used as a boundary or grave marker. In Uganda it is widely cultivated as a boundary hedge and grown scattered in coffee and banana plantations. In Kampala, this tree can be found within Makerere II Zone C, Mawanda road among other places.

An erect, stiffly branched succulent shrub or small tree 3-4 m.

BARK: thin and yellow-grey with a papery peel; an unpleasant milky sap when cut.

LEAVES: alternate and simple with 3-5 shallow lobes, to 15 cm long, widely rounded at the base on a stalk to 16 cm.

FLOWERS: small, yellow-green, shortly stalked on branched heads with a shorter stalk than the leaves.

FRUIT: ovoid capsules, slightly 3-angled 2.5-4.0 cm long, black when ripe, containing 3 mottled seeds. When crushed the seeds produce a yellow oil.

Edible: tender young shoots can be cooked and used as a vegetable, young leaves may be safely eaten when steamed or stewed, ashes from the roots and branches are used as cooking salt, cooked nuts can also be eaten. http://tropical.theferns.info/viewtropical.php id=Jatropha+curcas

Medicine: bark, thin twigs, leaves, the latex, seeds, oil from the seeds, root bark, flowers, cotyledons. http://tropical.theferns.info/viewtropical.php id=Jatropha+curcas

Agroforestry: used as a living fence in fields and settlements, can be used as a hedge to protect fields, used as a support for vanilla and other climbing crops, for soil-erosion control, all plant parts can be used as a green manure.

The branches are used as a chewing stick for cleaning the teeth and strengthening the gums.

The viscid juice of the plant when beaten, foams like soapsuds. Children often blow bubbles of it with a joint of bamboo.

Leaf juice stains red and marks linen an indelible black. The 37% tannin found in bark yields a dark blue dye, latex also contains 10% tannin and can be used as marking ink, ashes from the roots and branches are used in the dyeing industry, and pounded seeds in tanning.

The seed oil, extracts of the seeds, and phorbol esters from the oil have all been used to control various pests, often with successful results. The seeds can also be ground and mixed with palm oil and then used to kill rats.

The wood, fruit hulls and seed shells can be used as a fuel.

Dried seeds dipped into palm oil are used as torches, which will keep alight even in a strong wind.

Jatropha oil is an environmentally safe, cost-effective renewable source of non-conventional energy and a promising substitute for diesel, kerosene and other fuels.

The oil is also used for making candles, soap and as an illuminant. 

It is also used to prepare varnish after calcination with iron oxides