Invades wetlands, forming dense stands that outcompete all native vegetation, threatening waterfowl and small mammal habitat
Threatens salmon streams by increasing silt deposition and constricting water ways, altering hydrology and degrading salmon habitat
Spreads by seed and creeping rhizomes that can grow 9 feet per season, forming thick mats of vegetation; Roots and seeds are transported along waterways
Common along roadsides and other disturbed areas; Can cause hay fever and allergies
How do I manage it?
Small patches can be dug up as soon as they are spotted; Make sure to get all root fragments
For larger infestations, clip flowers before they mature to prevent seed set; Regular mowing will prevent plants from going to seed, but cut stems can be difficult to distinguish from native grasses
Mechanical controls are labor intensive and require long-term monitoring and re-treatment; Selective herbicides are effective
Plants may re-establish from seeds even after control; Difficult to impossible to eradicate once established