Purple Butterbean (Phaseolus lunatus): Identification and Edibility

The plant with purple vines, leaves, flowers, and hulls, climbing 12 feet, with dry black seeds edged in white, is likely a purple-seeded lima bean, Phaseolus lunatus (butterbean is a common name for large-seeded limas).

Key traits: Purple pigmentation (anthocyanins) in stems, leaves, pods. Seeds black with white hilum edge when dry.

Edibility: Most Phaseolus species are edible when cooked thoroughly. Raw lima beans contain linamarin (cyanogenic glycoside)—always boil 10+ minutes. Do not eat until positively identified. Castor bean (Ricinus communis) is the only common garden seed registered as highly toxic.

To verify: Search "purple lima bean" or "Phaseolus lunatus purple" for images. Compare your seeds to known varieties like 'Christmas Lima' or 'King of the Garden'.

Contact your state extension service for definitive ID before consuming.