Family: Fabaceae
Introduced to Hawaiʻi by James Macrae in 1824, the pigeon pea is a small tree that has naturalized in a few areas but is not considered weedy. The native origin is obscure due to its long history of cultivation. Evidence of breeding was found in Egypt, dating back to 2000 BC.
The beneficial plant provides a plethora of uses and products: livestock forage, nitrogen fixation, human food, green manure, support of vanilla orchids, hay, medicine, flour, windbreaks, silkworm food, fuel, thatching, and weaving materials.
A semi-perennial shrub, pigeon pea, requires replanting every 3 to 4 years.
Trifoliate leaves (sets of three), zygomorphic yellow flowers, molted red seed pods, and a deep taproot are some descriptive characteristics of this plant.
Plant Uses:
- Cultural significance
- Edible
- Erosion control
- Hedge
- Medicinal
- Nitrogen fixer
- Windbreak
Plant Dangers:
- No dangers
High Risk Traits:
- Naturalizes in disturbed areas (e.g., Hawaii, Florida, South Africa)
- Broad climate suitability (tropical/subtropical, wide altitudinal range)
- Tolerates a wide range of soil types (sand to clay, acid to alkaline)
- High seed production (>1000 seeds per square meter)
- Self-compatible (can reproduce without pollinators)
- Host to recognized pests and pathogens (e.g., Helicoverpa armigera)
- Propagules can disperse as produce contaminants
- Herbicide tolerance reported (though evidence is vague)
Low Risk Traits:
- Highly domesticated; no truly wild populations
- No evidence of weedy races or cultivars
- Not reported as a garden, agricultural, or environmental weed
- Palatable to grazing animals and non-toxic to humans and livestock
- No spines, thorns, or burrs
- Does not form dense thickets
- No vegetative reproduction (propagates by seed only)
- Poor tolerance to fire, heavy grazing, or cutting
