Ecological Impacts
Little research has been done on the ecological effects of flowering rush invasion on natural habitats (Lavoie et al 2003). Flowering rush does have the ability to produce dense stands (MNDNR 1999, Lavoie et al 2003). It can grow so densely that it interferes with recreational and industrial shoreline uses (Boutwell 1990 in Eckert 2000). Anderson et al. (1974) noted that it "appeared to be out-competing the willows and cattails" along the Snake River in Idaho. In the St. Lawrence River watershed, Lavoie et al. (2003) consider it to be more aggressive at moving into natural communities than purple loosestrife (Lythrum salicaria L.), though its effects on plant diversity appear to be more modest. They surmise that unlike purple loosestrife, flowering rush's growth form doesn't allow it to fill the available space, thus allowing other plants to persist at low levels within the patches. Flowering rush's effects on fish and wildlife are so far unknown.
Status in Area
Flowering rush is locally well-established in the upper Great Lakes region. It is considered invasive in Minnesota, Wisconsin, and Michigan. Sale and possession of flowering rush is banned in Minnesota (MDA 2001).