Crotalaria sagittalis, also known as arrowhead rattlebox or just rattlebox, is an annual wildflower in the Fabaceae or Legume family that is native to eastern and midwestern United States. C. sagittalis grows 6-12 inches tall with alternating short-petiolate leaves and a yellow flower, then producing a plump seed pod that will rattle when shaken. It is a member of the Crotalaria genus, which has 500 members commonly known as rattlepods. USDA Hardiness Zones 3 to 8. Crotalaria sagittalis seeds should be soaked for 2 hours in warm (not hot) water. Most seeds will swell up and should be sown immediately from there. Seeds that do not swell can be gently scarified and soaked again. Sow seeds on the surface of any well draining soil mix and press them in lightly. Very lightly sprinkle a thin layer of soil to cover the seeds. Keep seeds moist and at temperatures around 70ºF. Most seeds will begin to germinate within 20 to 30 days. Even with optimal conditions, germination may be slow and sporadic.