Anatomy of a medusahead invasion

An annual grass worse than cheatgrass

Medusahead grass has the ability to take over a landscape like cheatgrass but nothing will eat it after it dies and dries out in the early summer months. It is becoming a huge problem in some areas and I’ve seen allotments with vast expanses where it is about the only thing that grows. Of course, if you’re the BLM, what else is there to do but renew the grazing permit and continue the degradation?

Anatomy of a medusahead invasion.
High Country News


  1. Craig Avatar

    Ken/Ralph it would be nice if you guys posted or set up a link if you have not about invasive weeds with pics on the right side of the blog! We all hike and see these but probably don’t realize what they look like.

  2. Ralph Maughan Avatar

    We are going to have a new format for this blog before long.

    I think that’s a good idea.

    Here us a good photo from the Wikipedia

  3. Craig Avatar

    This is the one the IFG has
    I don’t think people have any clue as to how bad this is and what problems it causes!

  4. Craig Avatar

    Also I was out Pheasant hunting and ran into about 5 acres of Cockle burrs are those native or an invasive weed?

    1. Pronghorn Avatar

      Native and widespread…

      Common cocklebur occasionally forms a dominant ground cover in open riparian woodlands, intermittent streambeds, and beach habitats [10,17,20]. A common cocklebur habitat type was described in the following publication:
      Range ecology and relations of mule deer, elk, and cattle in the Missouri River Breaks, Montana [20].

  5. Ken Cole Avatar

    Another issue with medusahead is that, like cheatgrass, it is highly flammable early in the summer so it increases fire frequency on the landscape. Through this change it can spread to the newly disturbed areas and take them over.

    There is a spot on the highway to Riddle, ID from Mountain Home where it is gaining a foothold. If there is ever a fire there it will become a real problem. It has been reported to the BLM but they have repeatedly ignored it. The cows are still there though.

  6. Pronghorn Avatar

    Unfortunately, weeds just don’t generate the same kind of emotional response that, say, wolf haters do, although weeds are far more destructive, IMO. I’ve seen dramatic changes in loss of native biodiversity in the past decade-plus. We’ve worked our fingers to the bone to control the weeds on the land we’ve occupied for 8 years, and have been paid off in bird diversity, snakes, rabbits, deer, bats, squirrels & chipmunks, etc. etc. But it’s a never-ending battle and I’m tired of my life being dominated by weeds every growing season. Once we got spurge under control, cheatgrass moved in, and we’ve been fighting that ever since. Last spring/early summer we had lots of rain and the cheatgrass exploded–taller than I’ve ever seen it (3 ft. in some instances). I hauled 42 garbage bags full of seed heads to a compost facility. That made a sizable dent, but it will be back with a vengeance. I was still pulling and bagging it in October! Our weed guy (the guy we hire to spray) works with us and is very positive about the progress we’ve made, but damn it’s depressing. I come home from walks/hikes literally depressed at the loss of native plants. Sometimes, when I see a native plant getting engulfed by a growing weed infestation, I dig it up and rescue it. Sorry, just the mention of another nasty invader set me off. Once you know and recognize weeds, a lot of one’s enjoyment of the landscape is lost because you understand what’s at stake, and that not enough is being done. It’s a lot like global warming.


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Ken Cole