Introduced from Europe as a garden herb, and now found sporadically across the United States.
An annual that reproduces from seeds. Plants germinate in the winter and mature in early spring, dying back as warm weather occurs.
Mature plants have many branches and grow dense, low patches over the soil. Stems are thin and weak, with short, soft, white hairs sparsely covering them. The leaves are alternate and well spaced along the stems, occurring on long stalks. Leaves are palmate and deeply lobed, with each lobe also slightly lobed to deeply wavy. Flowers also arise on long stalks that are well spaced along the stems, usually accompanied by additional leaves. Flowers are pink and occur in small clusters. Seed pods develop as a swollen base with a long extension, which separates into twisted spines as it dries.
Characteristicts Important to Control:
Physical removal of small infestations is effective. A contact or systemic herbicide will kill larger infestations.