Finnman, this fireweed looks like our purple loostrife, I wonder if it is the same plant?
Purple Loosestrife (Lythrum salicaria L.)
P. Harris and J. Corrigan
The problem1,3,4: Purple loosestrife was introduced from Europe in the early 1800s. By 1900 it had spread widely in eastern North America. It was noted as an aggressive pasture weed of flood plains in Quebec in the 1930s and a problem in southern Manitoba in the 1950s. Currently purple loosestrife dominates many wetland habitats from the Maritime provinces to the Great Lakes, but distribution is still spotty in western Canada with the most extensive infestations in Manitoba and British Columbia. Most Canadian infestations are south of latitude 51Â° N, but plants occur north of 56Â° N, and should spread further north as the limit in Europe is 65Â° N.
A purple loosestrife plant can produce over 2 million seeds. Both seeds and seedlings float, so spread is rapid in moving water. Seedling establishment requires open moist soil or organic debris and often occurs on bare shores exposed by dropping water levels. Purple loosestrife forms stable stands, and can invade undisturbed marshes to displace up to 60% of the native vegetation. It has low palatability to vertebrate herbivores and suffers only minor damage from native insects, so stands support little wildlife. No herbicides are registered for use against purple loosestrife in Canadian aquatic habitats and plants regenerate readily after mowing.
On the positive side, loosestrife is a copious honey producer, although the grade is low, and the flowers are showy. In the 1950s several widely used horticultural varieties were produced by hybridizing and increasing chromosome numbers. However, since its noxious weed designation in five provinces, the nursery industry has substituted Liatris, which also has a purple flower spike.