Senna italica aka Spanish Senna

Senna italica is in Fabaceae, the pea family. People call it Italian senna or Spanish senna. Its native range spans Africa to the Indian subcontinent. This range includes Arabia, Iraq and Iran. It grows where the climate has a clear dry season. In tropical Africa, it grows in dry grassland. It also grows near streams and along roads. It grows on ground that people have disturbed, too.

This plant can be an annual, perennial or subshrub. Annuals live one year; perennials live for more than one. A subshrub has a woody base. Useful Tropical Plants calls it a small, deciduous shrub or perennial herb. It grows to about 2 feet [0.6 metres] tall. Its stems often lie on the ground, not upright. It is deciduous: it sheds its leaves each year. Its flowers tend to bloom in the rainy season. It forms seed pods that people collect for use as medicine.

Italian senna suits farms and gardens in drier tropical and subtropical regions. Give it full sun and soil that drains well. It prefers deep sandy loam that is not too rich or poor. Growers raise it from seed, often sown straight into the ground. Soaking seeds in warm water for 12 hours can help them sprout. Rubbing their seed coats with sand can help, too. Both methods can cut the wait for seeds to sprout.

People grow this plant as a useful crop. They also gather wild plants across the drier tropics. A crop yields for no more than three years. Plants that grow back on their own can renew a planting. Root lesion nematodes, a type of worm, can attack it. In trials, added mycorrhizal fungi helped the plant grow. Reports say it cannot fix nitrogen, unlike many pea family plants. This means taking nitrogen from the air for use. Do not assume it will enrich soil this way.

People have long used the leaves, pods and mature seeds as laxatives. Research links this effect to compounds called anthraquinones. The leaves have more of these compounds than the pods. In the Sahel, people eat young seeds as snacks or vegetables. But mature seeds can cause purging, or severe loose stools. This difference matters when you consider eating the plant. People sell dried leaves and pods locally for use as medicine. They also sell powdered leaves abroad as a hair conditioner. Sellers call it neutral henna or blonde henna. It can tint hair yellow rather than red.