ENVS 605

What is it?

Russian knapweed is a non-native, deep-rooted perennial. It spreads by aggressive, creeping, horizontal roots that are black with a scaly appearance. It most commonly produces flowers from June to August and sets seed in late summer into early autumn. Buds on the horizontal root can form shoots that can grow to be independent plants.

 

Why is it a problem?

Russian knapweed contains a toxic substance that inhibits the growth of surrounding competing plants (allelopathic). This substance may also be toxic to horses and livestock when consumed in large enough quantities. Like many invasive plant species, Russian knapweed displaces native vegetation and reduces proper forage on range and pasturelands. Russian knapweed prevails in many different land types make it a successful competitor.

 

Management Techniques:

• Prevent its establishment through proper land management

• Mechancial/Physical Control – this includes hand pulling, flooding and burning.

• Herbicides – Herbicide application control includes application of EPA-registered herbicides that target noxious weeds. Herbicides are used to spot treat noxious weeds

• Biological Control – The nematode Subanguina picridis is not yet available to the public, however research of the gall forming nematode indicated it is an effective management technique for the Russian Knapweed

• Planting competitive native plant species to occupy bare ground once infested by the weed

 

What we can do:

The most important thing you can do is avoid spreading of the knapweed by maintaining healthy pastures and preventing bare spots caused by overgrazing. Bare ground is prime habitat for Russian Knapweed invasion. Additionally, mowing can stress the knapweed and force them to use nutrient reserves in their attacking root systems.

 

Entities working on this invasive in the Gunnison Basin:

Russian Knapweed is included in the BLM's current Noxious Weed Plan. However, according to the Gunnison Office Rangeland Management Specialist, Russian Knapweed currently has a small presence in the Gunnison Basin. A hard copy of this can be reviewed at the BLM Gunnison Field Office located at 210 West Spencer Street, Gunnison, CO 81230.

 

General Information on Russian Knapweed:

National Forest Service 

• This field guide discusses the best techniques for managing Russian Knapweed in the Southwest

 

Colorado State University’s Noxious Weeds Brief

• This brief provides the general public with physical, biological and mechanical control techniques