Comments: Cornus spp. are natural early successional components of many woodland ecosystems in North America. They have many adaptions that enable them to take advantage of open areas, including a large number of seeds, vigorous seedlings and rapid subsequent growth, dispersal by birds, and high tolerance to adverse conditions such as drought and shade (Smith 1975, citing Auclair and Cottam 1971). Rapid and extensive cloning by rhizomatous growth allows dogwood species to create dense thickets which crowd out desired grasses, sedges and forbs, and alter wildlife habitat. Invasion of dogwood, along with other woody species, into prairies and wetlands became more extensive mainly due to the post-settlement decline in wildfires.
Woody plant invasion of floodplains is a concern in some areas, particularly in the western U.S., where stream diversion has greatly reduced the flow in rivers. Water diversion can reduce river flow to the extent that dogwoods and other woody plants invade the floodplain, reducing river channel width and drastically altering wildlife habitat. For example, woody plant invasion, including C. drummondii, willows (Salix spp.), green ash (Fraxinus pensylvanica) and black locust (Robinia pseudoacacia), has reduced channel area of the Platte River in Nebraska by 50-85%, resulting in a loss of up to 97% of the roosting habitat for sandhill and whooping cranes and many other migratory birds (Currier 1987).