Noxious weed of the month: Russian knapweed


By Ethan Proud

Special to The SUN

Russian knapweed is a drought-hardy plant and is spreading from the Arboles area up into Pagosa Springs and the Pagosa Lakes area. Two other knapweeds occur in Archuleta County, diffuse and spotted knapweed, which occur throughout the county, including Chromo.

Unlike its biennial counterparts, Russian knapweed is a perennial that spreads not only by seeds, but through its roots as well.

Due to its vigorous root system, it should not be pulled, though tilling can offer some control and mowing can be done every two to four weeks to exhaust the root reserve and prevent flowering and seed set. Both tillage and mowing need to be repeated frequently over a period of years to achieve adequate control. Russian knapweed chokes out native vegetation and forms a monoculture, which stops native plant establishment. Russian knapweed causes chewing disease in horses and has no cure. Herbicide treatments can be done at all life stages, but the label must be followed. Winter treatments can be effective if conditions permit applications.

Biological controls are available for Russian knapweed, but in order to be effective, competitive native species should be planted. Russian knapweed is allelopathic and secretes chemicals from its roots to inhibit the growth of other plants.

CPR and first aid classes

CPR and first aid certification classes are offered monthly by the CSU Extension office on the second Monday and Wednesday of each month from 6 to 10 p.m. Anyone needing to receive or renew certification can register by calling the Extension office at 264-5931.

We will also attempt to schedule classes on additional dates with five or more registrations. Cost for the classes is $80 for combined CPR/first aid and $55 for CPR, first aid or recertification. The type of first aid information provided will vary by the needs of the audience.