Curbing noxious weeds

Weeds are thieves, not only in the night, but also in the day.

They steal the land’s productivity and diversity, forage for wild and domestic animals, and even the soil itself, say experts from the Montana Weed Control Association.

In fact, researchers estimate that spotted knapweed alone cost Montanans $42 million last year.

So two women with divergent production techniques work diligently to reach a common goal: control noxious weeds on their land.

Key Points

• Noxious weeds steel plant diversity and the soil, costing millions to control.

• An integrated weed management strategy, using various control tools, works best.

• Diligence is the most important component of control


Sara Taliaferro works with her husband, Mark, and their daughter and son-in-law, Adele and Kip Stenson, of Dupuyer, Mont., to control leafy spurge and thistles, among other weeds, on their 4,000-acre cattle ranch.

“I don’t have much to say. I just spray,” Sara says.

Lately, she has directed her spray more effectively. Kip now uses a GPS unit to record where the weeds grow.

“The big thing is to remember where you found them last year,” Sara says when she and Mark load a spray rig into the back of their Ford Ranger.

Jan Boyle and her husband, Rich, concentrate on white top and spotted knapweed at their certified organic 120-acre Golden Willow Botanicals.

Jan, of Simms, Mont., surveys her pastures as she jogs and walks her dogs. Then the mower revs up.

“The white top will grow again from its roots, but it’s not spreading,” Jan says. “I think it uses so much energy to re-grow that it doesn’t spread.”

As an organic producer, Jan is not allowed to use herbicides on her weeds, so she makes a concerted effort to mow them as they flower.

“We can’t eradicate the knapweed because the irrigation ditch conveys the seeds. Our goal is control,” she says.

Both women notice a marked improvement in production on their land. Both attribute that increased production to their diligent weed control efforts, even though they use different tools to achieve that control.

“And besides, we’re supposed to be stewards of the land,” says Sara.

Tools to control weeds

Landowners may use several methods to control noxious weeds on their property. In fact, an integrated strategy usually is most effective. Various methods work better on different plants and each method has advantages and disadvantages. Effective weed control methods include the following:

• Burning and revegetation. Works for large areas. Burning alone might give weeds a competitive advantage.

• Biological. Insects can suppress weeds, but not eradicate them. Once insects are established, they can spread. Often control is slow while insect populations increase.

• Herbicides. Herbicides can target and control specific weeds quickly, but most have side effects.

• Manual hand pulling, mowing, disking. Optimum timing is important. Manual control requires manual labor.

• Prevention. The most cost-effective method. Requires education and planning.

• Targeted grazing. Type of grazing animal, timing and rate of grazing can reduce noxious weeds less expensively than other methods. The grazing manager must watch closely so desired plants are not overgrazed.

Weed list online

Montana law requires landowners to control noxious weeds so they do not go to seed. Currently, 32 plants are listed as noxious weeds within the state of Montana. To view that list, visit www.mtweed.org/weed-identification/.


This article published in the January, 2010 edition of WESTERN FARMER-STOCKMAN.

All rights reserved. Copyright Farm Progress Cos. 2010.