Senecio vulgaris

Common groundsel is a winter annual weed in the Asteraceae (daisy) family, is referred to as a summer annual, yet this plant can germinate in spring, summer, or fall. Native to Europe, North Africa and temperate Asia, it is believed to have arrived in North America mixed with grain that was brought by settlers. The common name comes from the Anglo-Saxon word groundeswelge, translating to 'ground swallower' which describes how quickly this weedy annual can spread.  

Common groundsel is most common in cool, moist conditions and can be found growing in ornamental and vegetable gardens as well as in forage and row crops. It is also found in disturbed locations such as roadsides, waste sites and cracks in pavement or sidewalks.  

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.  It is believed that a plant can produce up to a million seeds in one season.  

Flowers can mature to produce seeds even after being hand weeded. If possible, do not let plants go to seed. With new transplants, inspect liners and pots and eradicate new infestations before they spread. Common groundsel is well controlled  by pre-emergence broadleaf herbicides labeled for use.  Unfortunately, there are no pre-emergence chemicals available for home use. Tilling the soil in both the fall and early spring will provide some control as well as covering the area is a thick layer of coarse mulch.  That will prevent the seedlings from growing.  

One of only two species that are consumed by the cinnabar moth caterpillar.

Insects, Diseases, and Other Plant Problems: A rust disease has been accidentally introduced from Europe that may impact populations.

Composting with other yard debris can lead to the plant spreading.