Canavalia rosea aka Bay Bean

Canavalia rosea is a perennial vine in the bean family, Fabaceae. Its common names include beach bean and bay bean. It grows across tropical and subtropical coasts and is native to Florida. It lives on dunes and at coastal bushland edges. Some plants grow inland beside roads or lakes. Its seeds float at sea and can reach distant shores.

In gardens, beach bean forms a low, spreading evergreen mat. Groundcover plants stand about 0.5–1 foot [0.15–0.3 metres] tall. Their spread depends on the space they can reach. They can also climb nearby trees or built supports. Useful Tropical Plants reports stems reaching 6.6–33 feet [2–10 metres] long. Older stems become somewhat woody. The green leaves grow alternately and have three oval leaflets. Each leaflet has a smooth edge and a rounded tip. Leaves fold during hot weather, helping the plant save water. They stay green rather than taking on fall color.

Small racemes bear pink or purple flowers among the leaves. Flowers appear year-round, with the main flush from summer through fall. They give way to firm, woody brown pods. These reach about 0.25–0.5 feet [0.08–0.15 metres] long. The pods draw less attention than the flowers or leaves. Ocean currents carry seed pods along the shore. The seeds resist water entry, which helps them survive sea travel.

Grow beach bean in full sun with well-drained, sandy soil. It also tolerates loam and acidic to slightly alkaline ground. Salt spray, strong wind, drought, and poor soil suit its coastal role. UF/IFAS lists it for USDA zones 9b–11b. Its roots help hold dune sand and reduce erosion. Garden uses include coastal planting, groundcover, and trailing over walls. It grows fast, so keeping it within bounds may take work. UF/IFAS reports no major pest or disease problems. It does not list the plant as invasive. Root bacteria fix nitrogen, which supports growth in poor soil.

Reports of food use need care because the sources differ on safety. Useful Tropical Plants records flowers as flavoring and cooked young pods and seeds as food. It also records folk uses of roots, leaves, and seeds as medicine. Those reports do not establish safe home use. UF/IFAS warns that seeds and pods contain canavanine and are toxic when eaten. This warning conflicts with the other source's lack of known hazards.