Sesbania herbacea aka Bigpod Sesbania

Sesbania herbacea belongs to the pea family, Fabaceae. Its common names include Colorado River hemp and bigpod sesbania. Kew places its native range in tropical and subtropical America. Useful Tropical Plants suggests that its original home may be Mesoamerica. Cultivation has helped spread it from Argentina to the southern United States. It grows both wild and in planted stands.

This fast-growing plant stands upright with fleshy stems. It has few branches, which spread wide from the main stem. Garden height figures fall around 8–10 feet (2.5–3 metres). A broader reported range reaches 2.3–13 feet (0.7–4 metres). Its life span depends on the climate where it grows. In places with frost, it grows as an annual. In frost-free areas, it can live as a perennial or subshrub. The main stem may turn woody as it ages.

It grows in fields, low ground, and forests on floodplains. Other sites include stream banks and the edges of old river channels. It also grows beside roads, railways, and crop fields. Open ground disturbed by people provides further habitat. In cultivation, it prefers moist soil and accepts several soil textures. These include sand, loam, and clay. It tolerates mildly acid, neutral, and mildly alkaline conditions. It can grow in full sun or light shade. Hot summers and low humidity suit it best. Even light frost can kill the plant.

The flowers have both male and female organs. Bees pollinate them, and the plant is self-fertile. Growers raise new plants from seed. Root nodules house bacteria that take nitrogen from the air. The plant uses some of this nitrogen for growth. Nearby plants may also gain from this partnership. People grow it to hold soil in place and improve it. Its bark yields strong fibre for nets and other items. Indigenous North American peoples valued it as a fibre crop. People also gather fibre from plants growing in the wild.

Its value lies in fibre and soil improvement, not food. Plants For A Future lists no known edible or medicinal uses. The seeds contain saponins and other toxic compounds. Eating them can cause severe diarrhoea and bleeding inside the body. The plant also has weed potential. This matters when choosing a place to grow it.