Priority: - Control
Tall, perennial, wetland herb that grows up to 3 meters tall with square, woody stems.
Leaves are opposite, dark green, and lance-shaped.
Spike of purple flowers found at the upper end of stems. Flowers have 5-7 petals which appear from July through October.
Perennial plant that reproduces by seed and root fragments. Each plant is capable of producing up to 2.5 million seeds that can be dispersed by wind, water, wildlife, and humans.
Habitat & Ecology
Thrives in open riparian areas, ditches, ponds, and wetlands.
Dense stands outcompete and replace native wetland vegetation; fills in wetlands thus endangering a wide variety of native wetland plant and animal species.
Pull or dig the plants out and ensure that all root fragments are removed to prevent re-growth.
For large patches, there are relatively effective biocontrol agents, for example Galerucella calmariensis and G. pusilla. These beetles feed on the plant stems in their larval stage.