A small cluster of purple loosestrife plants can spread and cover a marsh in as little as one growing season. An infestation dramatically reduces biodiversity. The plant provides no food for native wildlife and infested areas are not used by nesting waterfowl. Wildlife habitat is destroyed. Purple loosestrife also grows along irrigation canals, drainage ditches, lake shores and wet meadows.
Purple loosestrife appears to reduce waterfowl, beaver and muskrat activity.
It can block waterways for boaters and fishermen. Purple loosestrife infestations can be found in every county in the Willamette Valley. Purple loosestrife is an intrepid competitor because it produces floating, pepper-sized seeds, as many as 2.7 million per older, mature plant. Birds, mammals and humans spread it by carrying the seeds in mud on their boots or vehicles. The plant has woody roots that form a dense mat, making it difficult to pull out.