Cudweeds (Gamochaeta spp.) are herbs in the aster family that serve as host plants for American painted lady caterpillars. There are about fifty plus species, and all are native to the Americas. Most cudweeds are annuals and can be either winter or summer annuals. They flower in mid-spring to early summer or in early fall. Some cudweeds can be biennial, meaning that they will form a basal rosette that can survive the winter and flower in their second year.
Purple cudweed (Gamochaeta purpurea) has gray-green, soft velvet-like leaves. Shiny cudweed (Gamochaeta coarctata) has leaves that are glossy green on the upper surface and white and densely hairy on the underside of the leaf. Wandering cudweed (Gamochaeta pensylvanica) has soft hairs and a light green color on both leaf surfaces.
Cudweeds tend to grow in open, thin turf and newly disturbed areas. Good cultural practices that encourage thick, dense turfgrass are the best ways to limit and prevent cudweeds from becoming established in your lawn. Information on proper fertilization rates and mowing height for your turfgrass can be found at HGIC 1201, Fertilizing Lawns and HGIC 1205, Mowing Lawns.