The “Bad” Grass List

Dog grass awns

The dog days of summer are upon us. Presently, my lovely dog Willow is sleeping off the heat in some ornamental grass by the house.

Dogs and grass awns

As a gardener, each season presents its own set of challenges. My biggest gardening woe during the summer season, surprisingly, isn’t squash bugs, fire blight, or drought. It’s actually grass. Summer is a time when my ornamental grasses and spring weeds go to seed, and produce awns that pose harmful and potentially deadly consequences to my dog (and any cat that roams my yard, for that matter).

It wasn’t long ago that my dog was scratching at her eye. I thought allergies were the culprit, and initially wasn’t too concerned. Several days later her eye grew red and swollen and I knew a trip to the vet was in order. Our dog had a Mexican Needle grass awn lodged in the side of her eye. After sedation to remove the awn, antibiotics to treat an infection it triggered, and a $500 vet fee we were on our way with a new understanding of the dangers grass awns pose to pets.

Mexican Needle Grass
Mexican Needle Grass

What are grass awns?

Whether you call them awns, Downy Brome, cheatgrass, foxtails, or any other number of colloquial names, to dogs they generally mean one thing – trouble. An awn is a hairy, or bristle-like, appendage growing from the ear or flower of barley, rye, and many types of widely grown grasses. These spikes and sharp edges serve a purpose – to stick and hold fast to surfaces so that they can propagate and spread their seeds to surrounding areas.

While part of the purpose of awns is to have them attach to passing animals and be distributed to other areas, this relationship is by no means symbiotic. These sharp ends can allow the awn to act like the barb on the quill of a porcupine, moving it ever forward into the skin and tissues of a dog.

How Do Grass Awns Injure Dogs?

Pretty much any contact a dog has with grass awns can be potentially hazardous. Grass awns can be inhaled, become lodged in the ears, swallowed, or even just imbedded in the coat or skin. It is when they are not quickly removed by the owner, or expelled by the animal, that they become problematic.

Obviously, this risk has quite a bit to do with where you live. A city dog is far less likely to come across awns, but even the most urban locales still have areas that have become overgrown with all types of vegetation. So, a working dog used for tracking or hunting might come across awns regularly, but an urban dog that spends a few moments exploring a neglected back alleyway might be even more at risk. The problems occur mainly when dog owners are unaware of the affect that awns can have to their dogs.

The “Bad” Grass List

Sometimes, knowing what not to plant is just as important as knowing what to plant. The following is a list of the most common grasses, identified by dog owners and veterinarians (and compiled by The Grass Awn Project), that pose a potential hazard to pets.

Cheatgrass/Downy brome Bromus tectorum

grass awn
Image Source

Ripgut Brome Bromus rigidus

Grass Awn
Photo taken by Andrey Zharkikh.

Canada Wild Rye Elymus canadensis

grass awn
Photo taken by rockerBOO.

Foxtail Barley Hordeum jubatum

Photo taken by Kazue Asano.

Needle and Thread Stipa comate

Photo taken by Andrey Zharkikh.

Western Needlegrass Stipa occidentalis

Photo taken by Matt Lavin.

California Needlegrass Stipa pulchra 

grass awn
Photo taken by NatureShutterbug.

Mexican Needle Grass Nasella tenuissima and Stipa tenuissima

Mexican Needlegrass Awn
Photo taken by (yours truly) Stephanie Gonzalez.

Sleepygrass/Tall Needle grass Stipa robusta

Image Source

Red Three-Awn Aristida longiseta

Image Source

Single-Awn Aristida Aristida orcuttianas 

<i>Aristida schiedeana</i>
Photo by Patrick Alexander.

Oldfield Threeawn Aristida oligantha

Image Source

What if I have these grasses?

If you like these grasses and don’t want to get rid of them in your yard, here are several ways to prevent them from harming your pet.

  1. Prune awns off ornamental grass before you allow your pet access to that area.
grass awns dogs
Here’s Willow again, safely spending time in her favorite sleeping spot, Mexican Needle Grass, with dangerous awns pruned off.

2. Weed wack and dispose of grasses with harmful awns, such as foxtails, before they go to seed.

3. Check pet’s coat and feet for awns regularly.

Despite my best efforts, I still find the occasional grass awn on Willow’s coat.

4. If your pet has a long or shaggy coat, it can be beneficial to have their hair trimmed short during the summer months to reduce areas awns can lodge and ease awn inspection.

For more information on ways to protect your pets from grass awns checkout The Grass Awn Project. And as always, happy gardening!

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Hello! I'm Stephanie - engineer by trait, gardener by heart, plant enthusiast, DIY lover, and creator of Never Enough Thyme. Here you will find garden inspiration, projects, and activities for kids.

2 thoughts on “The “Bad” Grass List

  1. We have to be careful to keep this out of our dog kennel…it likes to grow along the fence. One of our dogs got some in her nose. It was awful! The vet couldn’t see anything when we got her there, so I guess she managed to sneeze it out.


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