Trailing crown-vetch

Securigera varia (crown vetch, formerly Coronilla varia) is a low-growing, sprawling herbaceous perennial of the legume family (Fabaceae), reaching 30–60 cm in height but spreading laterally by creeping rhizomes to form mats up to 1–2 m wide. The slender, weakly ascending stems bear alternate, odd-pinnate compound leaves with 15–25 small, oblong, fern-like leaflets. From early summer into autumn it produces dense, long-stalked axillary umbels of 10–25 small pea-like flowers each about 13 mm long, bicoloured pink and white to pale lilac. The fruit is a slender, four-angled, jointed legume 2–6 cm long that breaks at maturity into one-seeded segments. The plant develops a deep, tenacious, branching root system that makes it highly effective for erosion control. Native to scrub, dry grasslands, and roadsides across Europe, North Africa, and southwestern Asia, it has been very widely planted in North America for slope stabilisation and is now considered invasive in many U.S. states; all parts contain the toxic glycoside coronillin.