Toxic Plants and Horses

When we bought our farm in DeLeon Springs, Florida, last year, I had visions of re-creating the lush native landscaping of the home we had sold. Because the focal point of that house was a beautiful live oak, it was nearly impossible for grass to grow. Rather than throwing money away at fertilizers, pest control and weed control, I opted for a native landscape of fern, azaleas, bromeliads and the like. Because I used no chemicals, the property was a certified wildlife habitat.

Our new farm was pretty barren….no grass, mostly sand and lots of oak trees. And weeds. One of the first things I did was to have the local home extension agent come out and walk our property with us, to identify toxic plants and to give me a plan for growing grass. Thankfully, the list of toxic weeds was very short. A cherry tree sapling on the other side of the fence, one night shade but lots and lots of elephant ears in the front of the property, where I planned on making my riding arena.

I waged war all summer long on those damn elephant ears. You can’t mow them, they grow back. If you pull them up by the roots, you better throw them in the yard waste for pick up because I learned that if you throw them on the burn pile and don’t burn them immediately, they just attach their roots right there and keep growing. I finally reluctantly gave in to chemical warfare, but that was also a temporary fix. The only sure way to kill them was to pull them and keep pulling them weekly until they finally gave up. The cold winter we had also helped kill them, but as spring approaches, I am keeping an eye out because I am sure they will re-appear. The good thing is that most of them are on the outside of our fence line and that field is currently off limits for grazing until it is firmly established. 
As I would drive around our small community, I could not help but notice that just about every farm had elephant ears in their pastures. One farm owner didn’t realize that they were toxic until I told her. 

And it’s just not elephant ears. I know many farms that have never bothered to identify toxic plants on their property. I worked at one very high end hunter farm that routinely had horses suffering from digestive ailments, rashes, hives and other issues. Their pastures were loaded with toxic weeds. Whenever I would mention that they should have the county agent out (for free even!), they declined, saying that they didn’t want word to get out that their property had toxic plants (but it was ok to be full of constantly sick horses?)

I envisioned my farm growing beautiful hedges and ivy along the fence line and barn walls, like you see in so many photos, particularly in England. Unfortunately, most of those plants are toxic. Every time I came up with an idea, I would consult the internet, googling toxic plants for horses or asking if a particular plant was toxic. Not only for horses, but chickens, goats and ducks. Sadly, a lot of what I wanted to plant is toxic. So I had to come up with a plan. For the plants that I really wanted, I created a space that is off limits to the animals….I have a picket fenced back yard where I grow all my favorite plants. For areas that my horses may be able to access, like along the fence line, I have planted horse friendly plants, like certain ferns and fruit trees. Along the outside of the fence is a wild grape vine which is safe for the horses and for about 9 months of the year, it covers a good majority of the fencing, which gives me that England atmosphere. Sadly, there will be no ivy growing on the barn however.

Horses colic and many owners hopefully treat it successfully, although many cases of colic either end up in surgery or sadly, are fatal. What many horsemen fail to realize is that colic is not in itself a disease. It is a symptom. It has many causes, whether it be sand, temperature change, eating while hot and sweaty, or it can be the result of eating toxic plants. Many times, owners overlook that the cause of the colic is a toxic plant. It is far easier to blame it on ingesting sand or the weather. Nobody wants to think that their pasture is the culprit.

Some toxic plants can be fatal immediately. Others may require days or weeks of ingesting them to slowly build up enough toxins to be lethal. Most toxic plants are not palatable to horses, but there is always that one horse who has to sample everything. In other cases, the pasture may not be anything more than sand and weeds and the horse has nothing else to eat and eventually is drawn to the toxic plant. Other times, poisoning can be a result of hay containing toxic plants. Therefore, it is important to 1) keep your fields weed-free and 2) buy your hay from a trusted source and inspect flakes before feeding for weeds (and other trash)

I am adding a list of some common plants that are toxic. Keep in mind that this is only a partial listing. 

-Locust tree. Causes weakness, cold extremities, diarrhea, weak pulse, colic. 

-Oak tree. Acorns produce tannin, which can be toxic if ingested in great amounts. Also, young buds cause problems in the spring. Colic, constipation, rough coat, anorexia, thirst, painful urination, kidney and liver damage and death are results.

-Black Walnut tree. Sawdust and shavings made from these trees will cause laminitis and death. Make sure you purchase shavings from a reputable source.

-Apple tree. Eating large quantities of apples can result in colic. 

-Wild Cherry tree. The leaves and seeds contain cyanogenetic glycosides, as do apricot and peach trees. Drinking water after consuming the leaves prompts the release of cyanide into the bloodstream, causing slobbering, convulsions and rapid death.

-Oleander. Cardiac glygosides are found throughout the tree. The smoke from burning the tree is also toxic. One ounce of leaves is enough to kill a horse.

-Boxwood. A popular landscaping shrub. Causes colic and death.

-Jasamine. Roots and flowers are most toxic. Respiratory failure and death.

-Hydrangea. Cyanide poisoning results from ingesting the plant. Causes death.

-Hemlock and Yew. Leaves, fruit and seeds are toxic. Causes death.

-Lantana. Causes colic, gall bladder inflammation, liver disease and death.

-Bracken Fern. One of the plants that builds up in system. After a month of ingesting, horses become uncoordinated, depressed and blind. Death will occur eventually if plant is not removed.

-Easter Lily, Rain Lily. Diarrhea, colic, death.

-Milkweed. Causes bloating, colic, seizures, labored breathing and death.

-St. Johns Wart. Increased heartbeat, diarrhea, sensitivity to cold.

-Crocus. Colic and death.

-False Hellebore, Indian Poke, Skunk Cabbage. Causes colic and death.

-Onions. Causes anemia, liver and kidney damage, death.

-Pokeweed. The fruits are minimally toxic, the flashy taproots are most toxic. Colic, muscle weakness, diarrhea.

-Buttercup. Salivation, depression, blindness, bloody urine, colic. Conditions of poison depend upon age and condition of horse.

-Larkspur. Colic, constipation, bloating and cardiac arrest.

-Nightshade. Toxic levels depend upon climate and stages of growth. The unripe berries have the highest toxin levels. Causes neurological and gastrointestinal disorders, bloating and congestion in lungs, heart and spleen.

Google is your best friend before planting a new flower or shrub. Here in Florida, it is a free service to have the county agent come out and identify toxic plants and help you come up with a game plan to develop a lush pasture. It is better to prevent your horse from eating a toxic plant than to try and find the reason for colic or other health issues that are unexplainable. Save yourself the heartache and walk your property and identify toxic plants and remove them now.

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  1. Add Spurge to the list — its everywhere, and while horses generally won’t eat it, there are a few who will, and I swear its the reason my mare ended up with severe ulcers that took two months of double Gastrogaurd to clear up.

    1. Thank you. It almost looks like creeping indigo. Where do you live that your horse ingested it? I had never heard of it until now.

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