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Trees Toxic to Horses: Identifying and Preventing Danger

Horses are majestic creatures that require appropriate care and suitable living environments. One important aspect to consider is the presence of trees in their pastures, as certain trees can be toxic to horses. While it’s true that horses will most likely leave trees alone if there’s enough grass, the possibility of a bored or curious horse nibbling on dangerous foliage still exists.

Understanding the types of trees that pose a threat to horses is crucial in maintaining their health and well-being. To mitigate risks, it’s essential to know which trees are toxic and take appropriate action to prevent ingestion. This article will cover several common toxic trees, signs of toxicity, and how to deal with potential problems to ensure the safety of your equine companions.

Key Takeaways

  • Toxic trees can pose a serious threat to the health and well-being of horses
  • It’s important to recognize common toxic trees and their signs of ingestion
  • Implementing preventive measures and knowing treatment options can help protect horses from harm

Understanding Equine Toxicology

Equine toxicology focuses on the study of poisonous substances and their effects on horses. It is essential for horse owners to be aware of toxic substances in their environment and how to prevent and manage exposure to ensure the health and well-being of their horses.

One of the main sources of toxic substances for horses comes from trees. Several tree species have components that are harmful to horses and may cause a range of health issues, from mild discomfort to severe illnesses and even death. It is crucial for horse owners to identify and remove these trees from pastures and ensure that adequate forage is available for their animals.

Among the trees toxic to horses are red maple trees, oak trees, and black walnut trees. Red maple trees, for instance, pose a significant risk specifically due to their leaves, which contain a toxin that can cause oxidative damage to horse’s red blood cells. To prevent red maple toxicity, it is crucial to minimize the horses’ access to these trees, routinely check pastures for fallen leaves after storms or high winds, and remove them immediately.

Exposure to toxic trees can lead to a variety of symptoms in horses, ranging from mild gastrointestinal upset to severe organ damage. Signs of toxicity vary depending on the specific tree, but common symptoms include depression, lethargy, weight loss, colic, and in more severe cases, difficulty breathing and organ failure.

In addition to trees, other plants can also be harmful to horses, such as certain types of shrubs or flowers. The ASPCA provides a list of toxic and non-toxic plants for horse owners to refer to as a valuable resource for maintaining a safe environment.

Managing your horses’ environment and being aware of potential toxic substances is key to ensuring their health and longevity. Regular inspections of pastures and surrounding areas, as well as understanding the signs of toxicity, can help horse owners prevent and quickly address any issues that may arise. By doing so, owners can protect their horses from the harmful effects of toxic plants and trees, ultimately creating a safer environment for their equine companions.

Common Trees Toxic to Horses

Red Maple

Red maple trees pose a significant threat to horses. The leaves of red maple trees become highly toxic after they have separated from the tree. The exact toxin is unknown, but consuming wilted red maple leaves can be fatal to horses. It is essential to monitor the pastures for fallen red maple leaves, especially during the autumn season.

Black Walnut

Black walnut trees are another toxic species for horses. The shavings from the tree can cause severe discomfort, known as laminitis, when used as bedding for horses. Symptoms include lameness, swollen legs, and increased sensitivity. It is critical to ensure that the bedding material does not contain any black walnut shavings.


Oak trees contain high levels of tannins that can be toxic to horses if consumed in significant quantities. The leaves, bark, and acorns of oak trees are the most toxic parts, with young leaves and flower buds being the most dangerous. Symptoms of oak poisoning include colic, diarrhea, lethargy, and dehydration. Horses should be kept away from oak trees in their pastures to prevent ingestion.


Locust trees, including honey and black locusts, are known to be toxic for horses. They contain toxins that can cause gastrointestinal distress if ingested. It is recommended to keep horses away from locust trees in pastures to avoid the risk of poisoning.


Cherry trees, along with apricot, peach, and plum trees, can pose a danger to horses when ingested. The leaves, bark, and seeds of these trees contain cyanide compounds. Consuming these parts can lead to symptoms such as rapid breathing, agitation, and potentially, death. It is crucial to keep horses away from cherry and other related trees in their pastures to prevent accidental ingestion.

Signs and Symptoms of Toxicity

Red Maple Poisoning

Red maple poisoning in horses occurs when they ingest wilted or dried leaves from the red maple tree. Symptoms of red maple toxicity include yellow/brown mucous membranes and dark red urine. Horses affected by red maple poisoning also display lethargy, refusal to eat, and increased heart and respiratory rates as their bodies struggle to receive enough oxygen.

Black Walnut Poisoning

When horses are exposed to black walnut tree shavings in their bedding, they may suffer from black walnut poisoning. Common symptoms include lameness, increased temperature, and swelling of the lower limbs. It is crucial to remove the affected horse from the black walnut shavings and seek veterinary care immediately to minimize lasting damage.

Oak Poisoning

Horses can experience oak poisoning by consuming a considerable amount of oak tree leaves, bark, or acorns. Affected horses may show signs such as weight loss, colic, and diarrhea. In severe cases, kidney damage may occur due to the toxic components in oak trees. Avoid planting oak trees in or near horse pastures to help prevent oak poisoning.

Locust Poisoning

Locust poisoning occurs when horses ingest the bark or leaves of black locust or honey locust trees. The toxic components in these trees can cause symptoms such as depression, lack of appetite, weakness, and even paralysis in horses. To protect your horses from locust poisoning, it is crucial to identify and remove any locust trees from their pasture.

Cherry Poisoning

Cherry poisoning in horses is the result of ingesting wilted leaves from black cherry or wild cherry trees. These leaves contain cyanogenic glycosides, which can cause rapid breathing, anxiety, trembling, and even death if consumed in large amounts. Recognizing the signs of cherry poisoning in horses and seeking prompt veterinary care is crucial to ensure their survival.

Treatment and Preventive Measures

Veterinary Care

If a horse is suspected of ingesting a poisonous plant, immediate veterinary intervention is vital. The veterinarian will assess the situation, provide appropriate treatment, and may administer medications to alleviate symptoms. It’s important to seek professional help as soon as possible, as some toxic substances can be lethal if not addressed promptly.

Pasture Management

Effective pasture management can significantly reduce the risk of horses coming into contact with toxic plants. Regularly inspect pastures for poisonous trees, such as oak and red maple, and remove them promptly to prevent ingestion. Ensure that horses have access to adequate forage, as well-fed horses are less likely to consume dangerous plants. Additionally, maintaining proper horse care and a clean environment can contribute to overall health and prevent horses from encountering toxic substances.

Plant Identification

Equine caregivers should be educated about local poisonous plants and how to identify them. This includes understanding the potential dangers of trees like junipers, boxwood, and certain pines found in horse pastures. Regular training and access to resources can enhance awareness and prevention. By being knowledgeable about the toxic plants in their area, caregivers can take proactive steps to ensure a safe environment for their horses.


When it comes to the safety of horses, being aware of toxic trees is essential. There are several trees that can pose a threat to the well-being of horses, including oaks, black locust, and trees from the Prunus family, such as cherry, peach, and plum. Exposure to these trees can cause a variety of health issues, including poisoning, damage to the digestive system, and even death.

Horse owners can take preventative measures by identifying potential threats in their pastures and removing or fencing off toxic trees. Additionally, ensuring horses have a consistent supply of safe and nutritious forage can help deter them from consuming potentially harmful plant material.

In conclusion, being conscious of the types of trees and shrubs present in horse pastures is crucial for maintaining their health. Continually monitoring and managing the environment for toxic plants, enhancing pasture quality, and providing appropriate care can lead to healthier and happier horses.

Frequently Asked Questions

What trees are poisonous to horses?

There are several tree species that can be toxic to horses. Some examples include the Adam-and-Eve, African Wonder Tree, Alocasia, and Oak tree. Other potentially toxic species to horses include cherry, peach, plum, locust, yew, oleander, mountain laurel, boxwood, elderberry, and buttonbush trees. It is important to be aware of the potential toxic effects of these trees to keep your horses safe.

Which oak trees are harmful to horses?

While all oak trees can pose a risk to horses, the problematic components are their acorns and fallen leaves in large quantities. Horses are especially attracted to oak leaves and acorns, which contain a substance called tannic acid. This substance can cause kidney damage and gastrointestinal issues in horses if consumed in excessive amounts. It’s crucial to monitor your horses and manage their environment to minimize exposure to oak trees.

Are all maple trees dangerous for horses?

Not all maple trees are toxic to horses; however, the red maple (Acer rubrum) is known to pose significant risks. The wilted leaves of red maples contain a toxin called gallic acid, which can cause severe anemia, difficulty breathing, and even death if ingested by horses. It is essential to identify the type of maple trees in a horse’s area and take appropriate measures to prevent ingestion of red maple leaves.

Are cedar trees harmful to horses?

Cedar trees, which belong to the juniper family, can be harmful to horses when consumed in significant amounts. Junipers can have toxic effects on horses, causing drooling, vomiting, diarrhea, and in severe cases, respiratory distress or seizures. Preventing horses from eating cedar and juniper plants is essential for their health.

Are pear trees toxic for horses?

Pear trees are not known to be toxic to horses. However, caution is advised if utilizing fruit-bearing trees as part of a horse’s environment. Overeating fruit or consuming rotten fruit can lead to colic or other gastrointestinal issues in horses. It is essential to monitor their access to fruit trees and ensure they don’t ingest excessive amounts.

What trees should be avoided around horses?

To keep horses safe and healthy, it is advisable to avoid having the following trees in or near their pastures: oak, cherry, plum, locust, yew, oleander, mountain laurel, boxwood, elderberry, buttonbush, red maple, and junipers. Ensure your horses’ environment is free from these species, and if they’re present, take necessary fencing or management measures to prevent access.

Last Updated on August 23, 2023 by Nate Dewsbury

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