Sesbania cannabina Seeds | Sesbania
LATIN NAME: Sesbania cannabina
COMMON NAME: Sesbania
Plant Profile
Sesbania cannabina is a fast, upright annual legume of Asian wet fields, growing two metres or more in a single warm season from fine, pinnate leaves and slender green stems. Through late summer it carries hanging clusters of small orange-yellow pea flowers, followed by thin, four-angled pods.
It grows naturally on wet, often saline ground, in seasonally flooded fields and along channels, and it has been used in Chinese agriculture for centuries as a green manure turned in before the crop. Its tolerance of salt and waterlogging is unusual for a legume and is the basis of its usefulness. The stems are hollow and tough, and were once used for cordage in its home region, which is the origin of the species name cannabina.
Science & Biotechnology
Sesbanias fix nitrogen faster than almost any other legume grown for green manure, and S. cannabina is the species of the saline and flooded soils of eastern China, where it was rotated with cotton and rice. Its tolerance of salinity has drawn study as salinity spreads through irrigated farmland, since a legume that grows where others fail is worth understanding.
The seed is hard-coated like most fast tropical legumes, and scarification or hot-water treatment is the standard way to even out germination. Its root nodules work with the same fast-growing rhizobia as the other sesbanias, and trials have measured the nitrogen returned to a flooded soil at levels that replace a third of a rice crop’s requirement.
Uses & Benefits
Its main use is green manure: sown thick in spring, it makes tons of green matter in ninety days and is turned in before it turns woody. It also serves as a fast shelter crop for young plantings, a forage on wet ground, and a demonstration of the legume family’s speed for students.
In the garden it fills a vacant wet bed in one season and feeds the next crop, and its orange flowers draw bees through late summer. Its fibrous stems have also been trialled for paper pulp, though the green-manure use remains the main one.
Growing from Seed
Pour hot water over the seed, leave it overnight, and sow the swollen seed two centimetres deep in warm soil or a moist, rich mix.
Germination takes under a week in warmth, and the plants grow visibly by the day; give them full sun and all the water they want.
Cut or dig the crop in before it flowers and sets seed, or the bed will be full of sesbania seedlings the following spring; on alkaline or salty ground the growth is slower but the salt tolerance still carries it. Where the ground is only seasonally wet, sow after the field drains and rely on irrigation, since the seedling stage wants constant moisture.
Our Take
Two metres of nitrogen-fixing green manure in ninety days, at home in wet, salty ground where few legumes dare. Cut it young and dig it in.
Related Reading
Gardeners who grow Sesbania often pair it with these related subjects: