The Carolina bush pea is a perennial herb with yellow flowers. It is used ornamentally in gardens and has nitrogen-fixing properties, improving soil fertility. Inputs Hardiness zone 51 Hardiness zone 61 Hardiness zone 71 Hardiness zone 81 Type Herb Perennial Functions Nitrogen fixer2 Footnotes Thermopsis villosa | Plants for a Future ↩ ↩2 ↩3 ↩4 Gaia’s Garden - A Guide to Home-Scale Permaculture, 2nd Edition Table 6-3 ↩