Tephrosia (Tephrosia vogelii) A perennial nitrogen-fixing legume reaching 6 feet tall, commonly used for soil improvement and as a natural insecticide. Native to tropical Africa, seeds require scarification for optimal germination, which occurs within 7-21 days at temperatures above 70°F. Seeds remain viable for 2-3 years. Plant 1/2 inch deep with 3-4 foot spacing in zones 9-11. Matures in 4-6 months before flowering. Exhibits excellent drought tolerance once established and resistance to most pests due to rotenoid compounds in its tissues. Special properties include its effectiveness as a green manure crop and ability to suppress nematodes when incorporated into soil.