Range: west-central North America, from Wisconsin to Mexico
Known as the slim-flower scurfpea or simply scurfy pea and classed by many as Psoralidium tenuiflorum, this US native legume is a common sight in the Great Plains and southwestern desert regions, ranging from southern Canada and the Great Lakes region to Montana, south into northern Mexico. A tolerant species, it is frequently found growing in open plains, sandy and clay soils, from open woodland to semi-desert regions. Mature plants form semi-woody bases and ephemeral shrubby growth every year up to 1 meter high and in some cases almost 2 meters across, branching heavily with spindly gray-green stems interspersed and tipped in nodes bearing whorls of 3-7 lobed leaves (typically 5), each lobe a separate leaflet roughly 1-4 cm long (sometimes up to 6 cm) and narrowly ovate to oblanceolate. Color is usually a bright to deep forest or grassy green. The ends of each branch once mature may terminate in a short inflorescence that may sport anywhere from 1-20 blooms, each flower barely up to 1 cm across at most and formed of a broad half-moon shaped upper lobe and two spreading lower lobes extending from a tubular, hairy calyx, all colored in varying shades of grape purple. Each flower is self-pollinating and will give way to a semi-rounded, spotted pod containing a single black seed. This species plays host to the caterpillars of the jaguar flower moth, which feed on the seedpods, and as a legume is capable of enriching nitrogen content in the soil.
Cultivation: Grow preferably in-ground (thick taproots do not lend well to container growth) in nearly any type of soil from sandy to clay, in locations that do not remain constantly wet. Does particularly well in high-plains or even moderately drought-impacted areas. Will tolerate growing in areas as cold as US Zone 4, and temperatures well above 100°F. Scatter seeds on the soil surface (scarification or a cold winter stratification may increase germination success), and grow in partial shade to full sun areas.
Lifespan and reproduction: perennial (above-ground portions die off each year). Reproduces via seed and possibly taproot offshoots, not conducive to cuttings typically.