Why I Hate Tall Fescue

Note: This article was written for the Bay Journal News Service which was published on May 27, 2014.  It was titled, “Please, Step on This Grass”.  Click here for a pdf copy.


I was in the Farm Coop store the other day in line to buy some garden seeds. The farmer in front of me ordered fifty pounds of Kentucky 31 Tall Fescue. I thought, “Oh my God, you poor dear, haven’t you heard”?

Close up of Tall Fescue.

Close up of Tall Fescue.

Those seeds are infected with an internal fungus that secretes an alkaloid that will be toxic to your livestock.

We should not plant another seed of Tall Fescue. Not only is it invasive and non-native (it’s native to Europe), it is toxic to just about everything that consumes it and it inhibits the growth of other plants.

Tall Fescue (Festuca arundinacea) is one of the most dominant grasses found in pastures, hayland, lawns, roadsides, wetlands and vacant lots throughout most of North America. It is almost always infected with an internal fungus, an endophyte (Acremonium coenophialum), which produces an alkaloid (ergovaline) that is toxic.

We’ve known for years its grave effects on pregnant horses: abortions, thickened placentas, and limited milk. Cattle get “fescue toxicosis” or “summer slump” which includes elevated body temperature, hoof rot, tail rot, lower conception rates and lower weight gain.

Cattle grazing too much Tall Fescue can get "fescue foot", a crippling condition caused by the toxins in the grass.

Cattle grazing too much Tall Fescue can get “fescue foot”, a crippling condition caused by the toxins in the grass.

In wildlife biology Fescue is known as the “F” word. According to most wildlife biologists it is the number one reason our Northern Bobwhite populations have plummeted. That’s because Tall Fescue forms a sod or mat so thick a bird can’t walk through it. Tall Fescue seeds are also toxic to birds. Fescue also creates excellent habitat for meadow voles, which attracts hawks and hawks also kill Bobwhites.

Tall Fescue is toxic to just about anything that eats it. Google it. It’s toxic to dairy cows, beef cows, horses, sheep, goats, birds, grasshoppers, ants and even nematodes. It also cuts down on biodiversity because it takes up space that native biota could have occupied and it’s aggressive.

Beef cattle in Poague Run before stream exclusion.

Cattle eating tall fescue during the summer will have elevated body temperature making them hot.  They will spend more time trying to cool off than eating which lowers weight gain.  Livestock should be excluded from streams because they destroy the steam banks and defecate in the water.

It’s also toxic to newly planted tree seedlings. This is called allelopathic, when one plant exudes a substance into the soil that inhibits the growth of other plants. This is one of the reasons many riparian forest buffer plantings failed. A two-year-old hardwood seedling inserted into a mature sod of Tall Fescue not only has to compete with the established fescue roots for nutrients and water; it has to overcome the toxins secreted by the endophyte in Tall Fescue.

Tall Fescue with seed heads.

Tall Fescue with seed heads.

It’s persistent in the landscape. I call it the toxic waste of the grass kingdom. It is difficult to get rid of. I once had a client tell me he bought a farm with Tall Fescue pasture. He wanted wildlife habitat. So he just “let it go” hoping natural succession would take place. Ten years later it looked exactly the same. The Tall Fescue formed such a dense mat that no seed could get through it and even if it did the allelopathic toxins would cause its demise.

So why does USDA still recommend it and how did it get here in the first place?

A brief history: Livestock farmers are always looking for grass that can produce feed for the longest period of time. University of Kentucky agronomists found what they thought was the “holy grail” of grasses in 1931 in a “holler” in the winter…it was green when all other grasses were dormant. They collected the plant and propagated it. The University released it in 1943 under the name Kentucky 31 Tall Fescue.

Oops. They did not know the plant had an internal fungus that produced an alkaloid that is toxic. We’ve been promoting it ever since, even though we discovered the toxic relationship in the 1970’s.

Okay, I’ll admit tall fescue is good for three things: erosion control, winter grazing and wiping manure off your boots.

Tall Fescue is good for erosion control because it is aggressive and can withstand abuse. Cattlemen have been using it for years to “stockpile” as winter grazing. In other words they take their cattle off of it in August, fertilize it with nitrogen, let it grow. then graze it during the winter. It is excellent forage in the winter because the toxins aren’t active in cool temperatures.

Cellulose digesting mobile protein factories.

We have diluted the tall fescue in our pastures by over-seeding them with clovers.

Okay, it’s everywhere and difficult to get rid of it. How do we deal with it? The first line of defense is to dilute it. Graze it hard then over-seed with clover. There are “endophyte free” varieties of Tall Fescue but these have not proven long-lived.

Two effective ways to kill Tall Fescue include tilling it to death, or a couple of applications of herbicide. Once killed, plant a more desirable forage.

The best remedy though is to never plant another seed of endophyte infected Tall Fescue. There are many other grasses that can produce forage for livestock without the side effects of the endophyte such as Orchardgrass and smooth brome. Let’s use them.


  1. Always informative. I am glad I have not ever planted any (to my knowledge).

  2. Buff Showalter says:

    How do you get rid of the stuff in rough riparian areas where it is impossible to disc or spray?

    • Bobby Whitescarver says:

      Buff, if it’s impossible to disc or spray you might have to just live with it. How about a backpack sprayer?

  3. Matt Yancey says:

    Buff has a thrifty young son that would work well with a backpack sprayer!

  4. Amanda Brown says:

    This is a prime example of how a simple lack of the proper education can have devastating effects. It is the responsibility of the government to step in, balance the pros and cons of it’s existence in a non native environment, and make the appropriate change. We need to move away from the quick fix mindset when it comes to our environment. Things need to start being considered from an ecological standpoint, not an economical one, when regarding our world and it’s ecosystems.

  5. Jordan Palamone says:

    Great article as usual professor. This is a prime example of the lack of critical information provided to consumers. They know the grass grows readily, but are completely clueless to the fact that Tall Fescue is toxic to livestock. This case of tall fescue gives us reason to fully understand the potential harmful effects that could arise from genetically modified food. Currently we are not allowed to test the effects of consuming GMO crops and we may be too late when we finally find a problem. I mean it took 40 years after the discovery of tall fescue for them to discover it’s toxic relationship. Hopefully we don’t rely on crops that have the potential for disaster.

  6. Caitlin Shipman says:

    Until reading this blog post, I was unaware of all of the harm Tall Fescue can cause. The part that boggles my mind the most is why is the USDA still promoting this grass when we now know that it is harmful to ecosystems and livestock? Certainly, Tall Fescue does more harm than good. I believe the steps listed to kill Tall Fescue should be taken by any farmer who values having a healthy pasture for their livestock.

  7. Susan Andersen says:

    It funny that you have us read this because I just read an article in Town and Country magazine telling rich people to plant different varieties of fescue in their yards to prevent soil erosion and the cut down on mowing. It actually looked really pretty in their yards, the magazine photographers did a good job with that one. Now obviously rich suburban yards are a completely different environment than farms. You don’t wants animals around to eat your grass in the suburbs so it wouldn’t matter as much that fescue can be poisonous there but the natural cycles that go on on farms shouldn’t be interrupted by a non-native, aggressive grass. It interesting that this grass is actually endorsed by several different sources even though it is harmful to the ecosystem around it.

  8. Ben Foster says:

    I am not a farmer by any means, but I have heard of tall fescue before and each time it was used in a positive connotation such as those mentioned above like erosion control and it being a hearty grass that can grow just about anywhere. I had no idea of its negative side effects such as secreting a toxic alkaloid. I feel that many people are in the same boat as me and are under educated in the topic. People should know both sides before buying products such as this. I will have to keep this message in mind the next time I hear Tall Fescue in order to educate people on what can happen if they are allowing there livestock to graze in fields of Tall Fescue.

  9. Oliver Allen says:

    I agree with Caitlin. I had to do a double take when I read that the USDA has put the “ok” on Tall Fescue grass. It seems contrary to the thought process that the USDA should have. This grass causes harm to the livestock and the other animals that feed on it. The livestock is then (in some occasions) processed and used as meat for the families in this country. While it may have benefits to it, Tall Fescue is not the grass that farmers should be using on their pastures.

  10. Allyson Ponn says:

    It’s unbelievable that such a common seed has such devastating effects. Until this class, I have never heard of this issue, and I was raised around livestock. It’s shocking to me that the Tall Fescue is still promoted by the USDA. I guess this is just another example of every solution have both the good and the bad. As you pointed out Professor, it’s great for preventing soil erosion however the toxin is obviously harmful. As others have stated in their comments before, education can go a long way. I’m glad you pointed out alternatives to use, now lets hope people listen!

  11. Leah Wilkes says:

    Wow! I am curious, so Tall Fescue is still very common in pastures. Is it well known that the tall fescue is harmful? Also what exactly does the internal fungus that secretes an alkaloid do??

    This sounds like yet another issue where education will help in the long-term.
    Very interesting and insightful article

    • Sara Guthrie says:

      I agree with Leah that education will be key in fixing this problem. Its hard to understand why the grass is still so prevalent when it causes such harm to livestock. I would have never thought that it was so harmful because we see it everywhere. It would be nice to see some more varieties.

  12. Nathan Irving says:

    I see this grass all the time all over the place and had no idea that it was toxic to practically everything. Definitely not something that is common knowledge, yet detrimental to crop growth and restoration of trees. It is convenient that the toxins are dormant in colder weather, which gives tall fescue some uses. But I wonder if there are other potential uses for tall fescue as biomass for energy production. Especially if it grows thick and pretty much year round. Could be something to look into.

  13. Anders Hasselquist says:

    It is interesting that as bad as the Tall Fescue is, it still serves some beneficial purposes for the environment. Obviously the cons far out way the pros of Tall Fescue and should be taken care of appropriately. I was wondering if there was any data of the economic impact Tall Fescue has on farmers with livestock? It would be interesting to see if removing all Tall Fescue would greatly increase livestock yields.

  14. Harley Burton says:

    Very informative article! I knew fescue was an invasive species, but had never understood the extent of its detrimental effects. I am sure that I am not alone in this lack of awareness. I find that many people support what is familiar without questioning its impacts, and fescue is yet another example. We have grown accustomed to seeing it abundantly in our pastures without stopping to think of its relationship to its environment, and the reasons why it thrives. Now it is clear to me that it survives as a product of its own toxicity and hindrance to neighboring species. People must become aware of these negative effects, and work towards eradicating this nuisance species.

  15. Brody Edwards says:

    Where im from there was a push to plant as much tall fescue as possible in pastures, along creeks and rivers(to prevent erosion), and along roadsides and it happened. People began planting tons and it was a good thing, it looked beautiful and it held the soil and water content when it rained. but, there was also a crowd pushing for it not to happen and this is because it is toxic to livestock and animals. now instead of a push to plant more, there is a push to get rid of it and go back to natural native grasses and fescue.

  16. Ben Petersen says:

    So does the USDA believe the benefits of Tall Fescue outweigh the negatives? It baffles me as to why Tall Fescue is still recommended. I agree with Amanda in the fact off I feel like there must be poor education on this subject. I really wonder if the farmer who bought the Tall fescue knew about the toxic alkaloid. To me, it seems like Tall Fescue is the easy way out. I’m guessing farmers still use it because it makes it easier for them to feed their livestock. Just my two cents.

  17. Jesse Peebles says:

    I didn’t realize that tall fescue was this bad towards the ecology around it and for that matter am a little lost as to why stores are selling it at all. Since it is native to Europe does it cause the same problems there as it does in the US?

  18. Josh Kugler says:

    Before this post, I really never heard much about tall fescue. However, its something that I am glad that I know about now. This article amazes me with the narrow mind of some people. You would think that if you were going to order such a large amount of a certain type of plant that you would do your research and determine if what you were buying was really going to help your farm instead of hurt it. I guess it is a situation where the idea/limited benefits of tall fescue have been passed down over the years and it is just natural for people to continue buying it. Personally, it sounds like farmers that purchase tall fescue are lazy or dont have the time to research into this plant. I guess that is something we will not be able to know. Great article. Glad to know what I know now because of it.

  19. Jackson Snarr says:


    Great article, and as always very informative. I had no idea how dangerous that pesky plant, Kentucky 31, was even though I have grown up around it all my life. I think the issue is, as with most of the blog you post about, clearly regarding education. Even though the plant on the outside seems like a very desirable grass to have in your field it is clear that the harmful effects of tall fescue in the warmer months outweigh any perceived benefits. I believe if the farmer who ordered 50 lbs of Kentucky 31 was educated about exactly what you know, ie. how harmful, and other viable options, I do not believe he would make the same purchase.

  20. Ashleigh Cotting says:

    I found this to be interesting because it seems to me like tall fescue could be useful when applied in the correct situation. Erosion control and winter grazing are both important uses that the grass can serve. However, because fescue has been used incorrectly for so long, it has a very bad reputation. It would be cool to see fescue used in the right environment where it could do some good.

  21. Jessanna August says:

    Because there are many other types of grasses that can accomplish the same results as tall fescue, I’m wondering if the reason for the continuation of planting tall fescue is related to poor public outreach warning of the plant’s toxicity. I was very unaware of the toxicity of tall fescue prior to reading this article. There needs to be more information on the harmful effects of the species. Perhaps the seeds are cheap, thus urging people to lean more towards tall fescue rather than some native plant. However, it just seems to make more sense that a native plant to the Americas would survive more effectively and benefit the land more than a nonnative species. Thank you for the warning Mr. Whitescarver!

  22. Codey Johnson says:

    Personally I have always kind of liked tall fescue, but that was before today. It was probably because I spent a lot of time outdoors as a kid and like you said, the stuff is everywhere. It was great for using as an imaginary sword and the seeds on the end were especially useful for smacking my sisters once or twice. As a little boy who enjoyed cowboys and Indians I would often stick a piece of fescue in my mouth just like it was a piece of hay and I was a cowboy, but after reading this article I probably wont be sticking the stuff in my mouth anymore. There are a lot of environmental wrongs we need to correct and i think we should add the spread of tall fescue to that list. It may not top the list but we can clearly see this grass is evil.

  23. Beginning in 2001 and finishing in 2013 I killed all of the toxic tall fescue on my quarter section cow-calf operation. Doing 10-15 acres/year I eradicated the nasty poisonous grass and replaced it with novel endophyte tall fescue. Universities, back in the 80’s recommended endophyte free tall fescue. In 1-3 years most of it died. Turns out the endophyte was the component that gave the plant the persistence to withstand heavy grazing, insect attacks, disease, extreme heat, etc. Then along came plant breeders with a novel endophyte. The novel endophyte gives the plant excellent persistence (as long as it isn’t grazed into the ground) but does not produce the dreaded toxin, erogvaline. My first stands are now 13 and 14 years old and going strong.

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