Home Pasture Health Forage Knapweed is the New Alfalfa

Knapweed is the New Alfalfa


If one of the many varieties of knapweed has popped up in your pasture, hooray for you! You’ve now got a very nutritious forage. It ranges from an alfalfa-like 14-19% protein in the rosette stage, and 10-12% when bolting.

Of course, too much knapweed can be too much of a good thing. So controlling it with grazing is a great way to go. Grazing it in bolting stage has been demonstrated to reduce seed viability by 90%, and successful grazing projects in the West have shown that a little persistence really pays off.

If you’re already saying, “But my livestock don’t eat knapweed! This is crazy!” Read on for information to change their minds.

Manage knapweed as part of your plan for pasture diversity

Let’s start our look at the beauty of knapweed as a forage with considering how it fits into a well-managed grazing operation.


Grazing knapweed

Based on my experience working in a wide variety of landscapes across the country, animals will eat a lot of this plant and ranchers who have trained their cattle to eat spotted knapweed have been pleased with the results. In the summer of 2010, Melissa Griffiths of the Madison Valley Ranchlands Group Weed Committee called to report on the progress of cows that had been trained to eat spotted knapweed the year before. Her message said, “We are doing the happy cow dance today. We went to check the pasture for spotted knapweed and it was all gone!” She said that there wasn’t even a plant left to allow her to compare what had been there to what had been eaten. Likewise, Wendy Braim of the 130 Mile Ranch in British Columbia, Canada wrote to say that her trained cattle “have really done a number on the plants in the big pasture at the 150 Mile. I am very impressed!”

The more intensely you manage, the more rapidly you’ll make a change. Here’s an example of Jim Gerrish’s example of high density grazing for knapweed control:

High Density Grazing for Spotted Knapweed Suppression

What’s the best time to graze?

This graph shows how much spotted knapweed, native forbs and grasses were grazed at high and low stocking rates for the months of June, July and August in a study done by Dr. Karen Launchbaugh.

Since spotted knapweed is a biennial or short-lived perennial, if you’re interested in reducing the amount you have in pasture, you’ll want to graze it to prevent seed production, while not putting extra pressure on the native grasses and forbs in your pasture.

A 2007 study done by Karen Launchbaugh indicated that in Idaho, July is a good time to hit spotted knapweed hard. Because it is more palatable then than the native forbs and grasses, cattle focus more on spotted knapweed. If you’re not in Idaho, look at your plants to tell you when to work on knapweed. Since green and growing plants are always more nutritious than plants in later stages of maturity, you’ll know that you can focus on spotted knapweed when it is green and the grasses are in seed.

If you’d like more on grazing to manage weeds, download my free ebook on it.

Managing Livestock to Meet Weed Management Goals – Free Download

How do we know that grazing impacts Knapweed? 

A 2008 clipping study found that clipping during bolting stage reduced viable seeds by nearly 90% compared with no clipping. That means that if you graze your knapweed hard, you’ll significantly reduce the seed bank. Keep in mind, that if you’ve had spotted knapweed for some time, you might have a pretty good seed bank. So you’ll need to keep grazing every year if you really want to get rid of spotted knapweed. That’s not such a bad thing though if you remember that every bite of spotted knapweed your cattle eat is just as good as a bite of alfalfa!

What about Russian knapweed?

According to the Colorado Department of Agriculture, Russian knapweed is found “throughout the United States west of the Appalachians and is most problematic in the semi-arid rangelands of the Great Basin and the Rocky Mountains.” Fortunately, it’s also a great forage. Here’s a little more about that.

Russian Knapweed is a Great Forage

Rancher Says “Russian Knapweed is Becoming My Favorite”

But my livestock don’t eat knapweed! This is crazy!

So, I’m not going to get into all the animal behavior science here about why your livestock don’t eat weeds because this article is already long. I’ll just sum it up by saying, “They don’t eat certain things because they don’t know its food.” When I learned this over twenty years ago, I started figuring out how to change their minds. In 2004, I began developing a simple method to teach cattle, and other livestock, to include weeds in their diet. Today, I can show you how to turn livestock into weed eaters in just 8 hours spread over seven days. They’ll remember forever, teach their offspring and herd mates to eat the weeds, and they’ll even try new weeds on their own. You’ll find all the resources and links to articles and videos you need right here:

Turn Your Livestock Into Weed Eaters

And the Funnies

Now that you’ve got a little to chew on, here’s a little Can-Can to go with the weed-eating story.

Weed-Eating Cows and the Can-can

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Kathy Voth
I am the founder, editor and publisher of On Pasture, now retired. My career spanned 40 years of finding creative solutions to problems, and sharing ideas with people that encouraged them to work together and try new things. From figuring out how to teach livestock to eat weeds, to teaching range management to high schoolers, outdoor ed graduation camping trips with fifty 6th graders at a time, building firebreaks with a 130-goat herd, developing the signs and interpretation for the Storm King Fourteen Memorial trail, receiving the Conservation Service Award for my work building the 150-mile mountain bike trail from Grand Junction, Colorado to Moab, Utah...well, the list is long so I'll stop with, I've had a great time and I'm very grateful.


  1. We have some 27 cousins who farm in Penna. We’ll send them each this article and your addy. Most are already using goats but those without livestock (one cousin has over 100 acres in market garden and pick your own) will like the training article. they can do this with deer. Even non-ag family will like it because using deer will reduce spring fire fuel loads. Very good article! You folks rock.

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