Weeds of Container Nurseries in the United States

Common groundsel is referred to as a summer annual yet this plant can germinate in spring, summer, or fall. Common groundsel is most common in cool, moist conditions. In milder climates or in overwintering structures, plants can survive outdoors in winter. Plants have distinctive lobed leaves and yellow flowers. Seedlings can flower when less than 2 inches tall but may grow to 18 inches. Seeds are wind-dispersed and have little to no dormancy, thus one can have multiple generations per year. Flowers can mature to produce seeds even after being hand weeded. Do not let plants go to seed in the nursery. Inspect liners before potting and eradicate new infestations before they spread. Common groundsel is well controlled by preemergence broadleaf herbicides available for nursery use. A rust disease has been accidentally introduced from Europe that may impact populations.