In North America, this tall herb has become naturalized in wetlands of northeastern states and adjacent Canada. In Ky. it has become established at several localities, but it does not seem to be as invasive here as further north. Colls. from CAMP, GALL and GRNP (KNK) are referable to var. tomentosa (P. Mill) DC., but that taxon is not recognized in recent treatments. At a site in Ontario, Rachich & Reader (1999) showed that Lythrum salicaria could not become established in stands of Phalaris arundinacea. Also, deer and rodents prevented flowering of Lythrum after its establishment in areas cleared of Phalaris. The authors suggested: "One mechanism underlying wetland invasion by L. salicaria is likely a combination of disturbance permitting seedling establishment and insufficient herbivory in disturbed areas to prevent newly established plants from surviving." An initial experiment with sheep was effective in N.Y. (Kleppel & LaBarge 2011). Biological control using insects from Europe is also showing great promise (Van Driesche et al. 2002).