How to Kill Knapweed: A Noxious Weed Found in Yards, Pastures and Forests
Knapweed is a common noxious weed found in many places: yards, alleyways, pastures and forest lands. True control of this weed takes a few seasons... if you are doing it correctly. In weed management, like bull riding, there is a fine line between a beautiful finish and a 0 score. While the 8 second ride is considered an art, Debbie calls weed killing, "common sense."
"Knapweed doesn't grow well in areas that are watered, fertilized with nitrogen or growing grasses that help to crowd out and compete well with knapweed."
That means, wait for it: take care of your properties!
"Many brands of weed killer help control knapweed. 2-4 D, Curtain Crossbow, Milestone and Feeder are a few brands. Mixing is important. This is where more is not better. Using more is dangerous to animals and humans alike. It changes the Ph of the water, and the chemicals won't work as they should. It does damage to periphery plants such as lawn grasses and pasture grass."
Spraying in the spring when the plants are out of dormant stage and begin bolting, flowering and seed-making will give you better control.
Spray before noon or after five when wind is calm and temperatures are under 80 degrees Fahrenheit. Always use a surfactant as a sticker. This acts as a glue to keep the chemicals on the leaves. It spreads like melted butter on toast, covering the leaf and keeping the pores of the leaves open to eat the waxy coating and fine hair that try to roll the chemical off as a self-defense for its survival.
We've got a selection of weed killer and fertilizer available online here.
Spraying in the fall will give you control of the next year's prospective weeds. The seeds that were formant will grow rapidly and lay dormant till the following spring. The roots will take in everything they can. By spraying them, it will kill the roots and the weed will not survive.
Want to add a natural component to the regiment? These bugs will really kill your weeds dead.
"There are insects for organic control that eat and destroy the roots and buds of the knapweed. These scary-looking angels are the root-boring beetle and moth. There are also two different seedhead gall flies, and a seadhead weevil. Also plant more grass, and water and fertilize it to further weaken the weed and have your portion of control."
By: Deborah Patterson, Master Gardener from Coeur d'Alene, Idaho
"I started working at D&B Farm and Home. I serve on Post Falls Urban Forestry, and help guide a 3-day hike for local fifth graders at a local park where I point out native trees, wildlife, and flowers growing in our area. I help raise two grandchildren one of them can't talk, so I learned sign language, and while not fast at it, I get my point across and find it helpful at work with a few of our customers."