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For the health of your horse

Pleun Broeren
20 april 2023 Reading time 4 minutes

Poisonous plants, trees and flowers for horses

Some pastures not only grow plants and flowers that are healthy for your horse, but also plants that can pose great dangers. In general, horses know very well which plants are poisonous because of their bitter taste but, in some cases, they eat it anyway. Currently there are about 80 (!) European plant species that are poisonous to horses. These poisonous plants can cause various symptoms. In addition to plants, there are also trees and flowers that are poisonous to horses.

How can you protect your horse from poisonous plants, trees and flowers?

Firstly, the best safety measure is not to let your horse graze in a pasture that you have not carefully inspected beforehand. Most poisonous plants taste very bitter, so horses usually do not eat these plants quickly. When there is too little grass in the meadow and/or the horse has too little roughage at its disposal, it may still happen that it will eat other plants that it does not like and which may be poisonous. In addition, some plants only develop a poisonous taste when the plant is fully grown.

Also, poisonous plants lose their bitter taste when dried. This means that your horse does not always recognize the poisonous plants as such, while the effect of the poison is not lost. That is why pruning waste is always so dangerous to give your horse, but also hay where the pasture has not been checked for poisonous plants. Never give pruning waste to your horse and make any local residents aware of this. Never buy hay from an unreliable source or from roadside grass!

Also, take a good look at the surroundings of the meadow. Which trees are next to the meadow and are they poisonous? And can your horse sense this?

Have you discovered a poisonous plant or flower in the horse pasture?

Then remove it as soon as possible. Make sure you pull it out of the ground, root and all. Also, do not forget that poisonous plants have different flowering periods and do not always stay in one place but, sometimes, also "roam" in the meadow. A one-off pasture check is, therefore, not sufficient. It is important to do this regularly. When there are poisonous trees or shrubs near the pasture, it is wise to ensure that the horses cannot reach them and the pasture is (partially) closed off during the period when they release their leaves or fruit.

Tip: Make sure that your horse does not pick up unfamiliar plants while riding. In a working state, horses are distracted and therefore choose their food less selectively or instinctively. This increases the risk of poisoning!

Horses and ragwort

Ragwort is one of the best known poisonous plants for horses. This plant grows very well, mainly from June to October on a clay soil enriched with nitrogen. Ragwort does not lose its toxicity after drying! It is, therefore, important to also check your hay for this herb. Once a horse has ingested ragwort, liver damage is one of the main symptoms. The damage to the liver is caused by the alkaloids from the plant. Apathy, depression, loss of appetite and weight loss are also recognizable symptoms of ragwort poisoning.

Is Jacob's Wort Deadly to Horses?

If a horse ingests ragwort over a longer period of time, small amounts can already have major consequences. Ragwort is deadly when an adult horse eats 14 kg of fresh, or 2 kg of dry ragwort. For a small pony 4 kg fresh or 0.5 kg dry plant applies. So be careful! Ragwort can be recognized in the meadow by its yellow flowers.

Horses and horsetail

Horsetail is a very poisonous weed for horses. It lives in damp places and blooms in the months of April and May. The important symptoms of horsetail poisoning are: increased irritability, staggering, paralysis of the hindquarters, jumpy and falling over. These symptoms are caused by the poisonous substance, thiaminase, in horsetail. This substance breaks down vitamin B1 in the horse's body. Horsetail is less toxic in dried form than in pasture but can still cause serious damage. Checking your hay is also important here!

Which plants, trees and flowers are more toxic to horses?

In addition to ragwort and horsetail, many more plant and tree species are poisonous to horses and new plants are constantly being added to this list. In general, trees and shrubs that remain green in winter can be classified as poisonous, but there are of course many more. If you are talking about highly poisonous plants in small amounts, the boxwood , yew and maple are certainly important ones to keep an eye on. Poisonous to a lesser extent, but certainly not suitable for consumption by horses, include the following plants, trees and flowers:

  • Acaciaboom
  • Bracken
  • Azalea
  • Bastard clover
  • Belladonna
  • Hogweed
  • Beech  
  • Bittersweet
  • Blue monkshood
  • Buttercup
  • Brake
  • Datura
  • Oak
  • Spotted and water hemlock
  • Golden Rain
  • Fall-timeless
  • Dog run
  • Poppy
  • Ivy
  • Tree of life
  • Privets
  • Nightshade
  • Narcissus
  • Rhodondendron
  • Robinia
  • Oleander
  • Pieris
  • Comfrey
  • Thimbleweed
  • Wolf's Milk
  • Black henbane

Note: this is not a complete list. As a precaution, our advice is, when in doubt about the toxicity of a plant or tree, do not let your horse eat it.

What to do if your horse has eaten a poisonous plant?

Unfortunately, plant poisoning in horses is not uncommon and not always 100% preventable. After poisoning, different symptoms can occur, depending on the amount and type of poison. Important symptoms by which you can recognize a poisoning are: digestive problems, swelling, skin irritation, shortness of breath, tremors, colic, excessive salivation, balance disorders, paralysis or death.

In the case of acute poisoning, a horse usually reacts immediately after consuming the poison. In chronic poisoning the poison accumulates in the horse's body and signs of the disease gradually become visible. If you see or suspect that your horse has eaten a poisonous plant, call the vet immediately. It is important for diagnosis and treatment that you know which plant, and how much of it, your horse has eaten. The vet can quickly start with the right treatment.

Non-toxic plants, trees and flowers

There are also many plants that many people think are poisonous, but actually fall under the non-toxic plants. For example, think of the plane tree, butterfly bush, purple dead nettle and lavender. 

There are also healthy edible plants, flowers, trees and herbs for horses. Herbs in the horse pasture can have a beneficial effect on the body processes.
A few examples of edible plants and herbs in the horse pasture are: Dandelion, Cow parsley, White and Red Clover, Chamomile, Daisy, Thistle. 

Tip: It is important that you are familiar with the names and appearance of poisonous plants and trees so that you can identify them and protect your horse. You can possibly make a poster with the pictures of the poisonous plant and the correct name. Below are some images of the common plant and tree species that are highly toxic to horses.


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