Does your acreage have Russian knapweed? Probably, because basically, it's everywhere!
It is one of the most widespread noxious weeds in western Colorado. It is widespread in lower elevations of Delta County but there is little knapweed in the eastern part of the county above 7,500 feet in forest settings. Russian knapweed (Acroptilon repens) is a non-native deep-rooted perennial that spreads by aggressive, creeping, horizontal roots (rhizomes) and seeds. Russian knapweed emerges in early spring, bolts in May to June, and flowers through the summer into fall. Russian knapweed is toxic to horses.
The best management plan includes competitive vegetation combined with mechanical and/or chemical control. Some chemical control is almost always needed before competitive vegetation can be established. Currently, biological control development is taking place under the direction of the Insectary in Palisade.
The most convenient and effective herbicide for the average landowner is called Milestone. Transline and Curtail are also effective. Applications may be made until the plant blooms and hardens off in the summer heat. Applications may be made in September and October if adequate moisture is available. Smaller quantities of Milestone in one-quart containers are available at local agricultural supply outlets. One quart is sufficient for four acres. Read the label carefully for mixing and application instructions. Wear appropriate clothing for application. Long pants, long sleeve shirt, socks, non-absorbent gloves, eye protection and a washable hat are needed. Remove and wash all clothing separately from other laundry.