Hemp sesbania

Hemp sesbania

Weed Flora of Mississippi

Prepared by

Taghi Bararpour and Jason Bond

Family: Fabaceae (Legume family)

Genus: Sesbania         Species: herbacea

History: Hemp sesbania is commonly known as big pod sesbania, Colorado river-hemp, coffeebean, and coffee weed, and the species is a native of North America.

Life Cycle: Summer annual.

Special Characteristics: Hemp sesbania is a prolific seed producer, producing up to 21,000 seed/plant. Seeds have physical dormancy maintained by an impermeable seed coat. They persist well in the soil seedbank, with 18% surviving 5.5 years of undisturbed burial.

Roots: Taproot.

Stems: Without hairs, may become woody with age.

Leaves: Exhibits compound leaves characteristic of legumes.  Leaflets are arranged oppositely, although individual leaves are alternate.

Flower: Two to six individual flowers occur on elongated inflorescences. Flowers are yellow and may be spotted with purple.

Seeds / Fruit: A pod containing 30 to 40 seeds and are linear, curved, 10 to 20 cm long.

Seedling: Cotyledons are spoon-shaped. The first true leaf is simple, subsequent leaves are compound and composed of six to eight leaflets that occur oppositely along the leaf axis (pinnately compound). 

Interference: Populations of 0.8 to 12.9 hemp sesbania plants/m² emerging with soybean reduced the yield of wide-row (1 m) soybean 10 to 80% when allowed to interfere throughout the growing season. A hemp sesbania population of 6.8 plants/m², competing with soybean for 6, 8, and 10 weeks after soybean emergence of soybean reduced soybean yield 18, 27, and 43%, respectively.