The “Bad” Grass List

By Kevin Noon and Cathy Lewis

Grass AwnWe currently know of or suspect several grass species as dangers to our dogs. These species have two characteristics of the floret that make them particularly insidious. The basal extension of the lemma (sheath or bract) around the grass floret comes to a very sharp point as the floret matures and dries out at the end of clip_image002the plants’ growing season. And the lemma is covered with tiny hairs pointing away from the sharp basal point. As the florets mature, they fall off easily. They can be inhaled into the throat or lungs of a dog, swallowed, caught between the toes, become lodged in the fur, or fall into the ear canal. Once attached, the direction of the basal hairs creates a “barbed” effect which keeps the floret from backing out of the fur or tissue. As the animal moves the floret constantly migrates forward pushing the pointed base further into the tissue.

Once inside the tissue these florets have been known to migrate anywhere inside the body including through organs, down the spinal column, through the eyes, and up the limbs. Aside from the damage and infection caused by the migration, some florets carry bacteria that can cause serious infections depending on where they are located.

The following is a list of the most common grasses with these characteristics that dog owners and veterinarians across the country have identified. The worst known hazards are shown in red. The links provided contain additional information and/or photographs.

Cheatgrass/Downy brome Bromus tectorum Photos in site Gallery
Ripgut Brome Bromus rigidus

Canada Wild Rye Elymus canadensis Photos in site Gallery
Virginia Wild Rye Elymus virginicus
Great photos:

Foxtail Barley Hordeum jubatum Photos in site Gallery
Awn photo:
Needle and Thread Stipa comate
Western Needlegrass Stipa occidentalis
California Needlegrass Stipa pulchra CA only
Sleepygrass/Tall Needle grass Stipa robusta
Winter Redtop/winter bentgrass/ticklegrass Agrostis hiemalis or Agrostis hyemalis
Red Three-Awn Aristida longiseta
Single-Awn Aristida Aristida orcuttianas CA, AZ, NM, TX
Oldfield Threeawn Aristida oligantha
Nimblewill Muhlenbergia schreberi
This plant was suggested as problematic by a plant biologist at U of Minnesota. On inspection, it doesn’t appear immediately to have an aggressive awn, but better to provide the information as potential hazard than not.

NRCS database (main):
Line drawings of various grasses/identification guide:
More photographs of many grasses:

© Cathy Lewis & Kevin Noon, 2010

12 Responses to The “Bad” Grass List

  1. Tracie Wilson says:

    Very informative site! THANK YOU for putting this information together in one spot for the rest of us dog lovers!!!

  2. Tracie Wilson says:

    Have you heard anything negative regaring Indian Grass?

  3. admin says:

    You’re welcome! I’m glad you find it helpful :-) .

  4. admin says:

    I have been told that a dog in Ohio had an infection where recovered plant material was identified as Indian Grass. We do have some in our training field, and I was pulling pieces apart all fall to examine. It’s all so soft I’m perplexed at how it could have caused a problem, unless there are different varieties identified as Indian Grass and another type features a more aggressive awn. I can hope we will have better information to work from as we are able to get more recovered material identified. If anyone needs assistance in that regard, please contact me.

  5. Danelle Oliver says:

    This is my first year growing warm season grasses in a test plot. One variety in my mix is Indian Grass. I was told that it can be dangerous to our dogs. After examining it and finding no barbs on the seeds. I wondered if the danger was that it could be easily inhaled due to the small light weight seeds that it drops, late summer early fall. A time we usually are running our dogs in fields.

  6. Mark Christenson says:

    Hi. I am a Veterinarian from Minnesota and received a question on new CRP plantings in Western North Dakota. They are wanting to try “Basin WildRye” in some CRP fields. Is there any reports of this being a problem in dogs like Canada wild Rye.

    Thank you any info appreciated

  7. Justin Feeman says:

    Hello, I was forwarded this website from all around dogloving stepmother who has trained, professionally groomed, and competed with dogs. I like dogs, but I like grasses better. I think that labeling grasses as “bad” is an injustice to the grass. Most of the grasses in your “bad grass” list are native grasses that are important to the ecosystem and have been in existence much longer than Spaniels. I suggest that you redefine your “bad grasses” as cautionary grasses or grasses incompatible with dogs so that people do not assume that the listed grass species are bad for anything but dog recreation.

  8. k Smith says:

    I would like to put these info in our magazine. Thank you

  9. Sarah parker says:


    I was wondering if you had any information about whether purple fountain grass migrates in a similar manner as the plants listed above. My dog may have inhaled some through his nose, and I am extremely worried. About a week and a half ago he was playing next to a purple fountain grass bush and suddenly came out of the garden with a severe sneezing fit. He sneezed about 30 times in a row, and has continued to have bouts of sneezing since. Before that day he had never been a sneezer. So far the vets have tried two different procedures and haven’t found the plant in his nose, and he is going in for a ct scan tomorrow. It is possible that he sneezed it out, but i worry he may not have given his continued bouts of prolonged sneezing since that day (and even after his nose was flushed). Cancer, alergies, an infection, and nasal mites have also been ruled out. If anyone had info. On purple fountain grass it would be much appreciated.

  10. admin says:

    Hi Sarah. I can appreciate your concern and wish I could offer some assistance, but I’m not familiar with this particular grass. The ongoing sneezing would worry me, too. I hope that this resolves quickly for your dog.

  11. Scott G. says:

    Question about cereal rye that is often used as a deer food plot cover crop, is the seed of this rye a barbed awn? Thank you for information you may have.

  12. Jamir Graham says:

    Just had the problem with grass seed . My bouvier had a raw patch on the top of her hind foot, I thought it was a sting or insect bite, 5 days later it was not clearing up despite cleaning the area and draining the 2 holes that had formed. Took her to the vet today, immediate anesthetic and open up her foot and behold 2 full grass seeds a good 2-3 inches away from the original “hole” area . and 2 babies in getting ready to travel around under the skin between her toes. !

    I have NEVER heard of this before , so absorbing your site material

    I was devastated for her, what a problem this has caused, never would have believed it if i hadn’t seen them with my own eyes, huge and travelled way past the areas that i was treating.

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