Idaho’s Noxious Weeds

Idaho’s noxious weeds include species that make significant modifications to the landscape. Purple loosestrife can change stream velocity, which increases siltation. Species such as spotted knapweed can accelerate soil erosion. Salt cedar deposits salt on the soil surface from below-ground alkaline water, which leads to the elimination of all salt-sensitive species. Areas within the Czech Republic are seeing reductions in native species because they have lost their pollinators to the nectar of Policeman’s helmet, another Idaho noxious weed. Bohemian knotweed is creating monocultures along many Idaho streams, where it lacks the bank stabilizing root system of our native riparian species.