Groundsel can be a winter or summer annual. It can be identified by its branched stems that are smooth and that frequently root at the lower nodes. The leaves are fleshy and sparsely hairy to smooth, and the lower leaf blades taper to the petiole. Blooming from June through October, Groundsel produces small clusters of flower heads that are composed of several yellow disk flowers. Reproduction occurs by seeds. NOTE: Groundsel contains alkaloids that can cause liver damage in horse and cattle, making it one of the more dangerous broadleaf weeds for agricultural reasons.
This broadleaf weed prefers areas with little competition and is often found growing in low-maintenance lawns, gardens, nursery plots and along railroads and roadsides. Groundsel can be found throughout much of North America.
Senecio vulgariscan be a problematic weed if conditions in your yard allow it to produce seeds in your lawn—this is especially common in cooler, wetter months. Although cultural weed control methods and good lawn management practices can help prevent this nuisance from going to seed, once it is present in your lawn, professionally selected and applied broadleaf weed killers are typically necessary for removal.