Why is it a problem?
- 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