Purple loosestrife was historically sold as a garden ornamental but is no longer available for purchase. Some hybrids that are still available to purchase may be able to cross pollinate with purple loosestrife enabling the hybrid to produce viable seed so deadhead hybrids if you are growing them. There is only one known historical site that has purple loosestrife in the Boundary which has had nothing growing there for several years but there may be more in private gardens. Please report the location if you see this plant.
Prevention is very important with this plant. We have the opportunity to eradicate this species from the Boundary. This plant is designated as provincially noxious. Do not share seeds with friends. Report it if you see this plant. It is sometimes confused with fireweed so learning to identify invasive plants is important to save time.
Most birds will not nest in loosestrife. Wetlands can lose 50-100% of their native plants when loosestrife invades which reduces the food supply of native species causing a reduction in diversity. Large infestations can block water flow in narrow channels which can effect fish movement.
This wetland perennial grows to be 1-3 m in height. It has a woody taproot as well as a branching fibrous root system. It has a 4 sided stem with opposite or sometimes whorled stalkless leaves. It has purple flowers that for in a spike. This plant can produce over 2.5 million seeds in a year. It is most often mistaken for the native Fireweed (Epilobium angustifolium) which normally grows in upland areas.