Amorpha furticosa- This has a real wide growing range across the county into Canada and Mexico. In California most of it grows in San Diego and Riverside County in semi-shaded north facing areas. Very dark purple flowers in late spring into summer. Excellent nectar plant for butterflies and bees. The leaves are one of the larva plants for the dogface butterfly caterpillars. How the butterflies find them, I don’t know but they do.