Common Plants Poisonous to Horses in the UK

Many plants are safe for horses to eat, but there are also a considerable number of plants that are poisonous growing in the UK. When consumed, reactions can range from mild irritation to severe colic or even death. As an equestrian, it’s incredibly important to know the names of these plants that are poisonous to horses, so if you spot them growing in your paddock you can uproot them before they become a problem.

Plants poisonous to horses in the UK

1. Ragwort

Many horse owners are familiar with the dreaded ragwort and rightly so as just 1 – 5kg of it can cause reactions such as liver failure or even death. It takes around two years for it to grow and flower properly and initially, it’ll appear as dense rosettes of leaves, then by year two, it will start to produce bright yellow flowers on long stems that range between 30 – 100cms.

Whilst it’s growing, horses generally don’t care for ragwort as it has a very bitter taste, but when it wilts or dries, it becomes quite palatable. Due to this, hay should never be made from fields containing this poisonous plant as it’s one of the few instances horses will happily consume it.

In the UK, local authorities also have the legal power to order landowners to clear land containing ragwort, but it’s best to remove it before it gets to this stage as once it takes hold, each plant is capable of producing thousands of seeds that disperse by the wind. Ragwort thrives on poor pastureland, so carrying out good field management is vital in eliminating it. Use horse-friendly herbicides or manually uproot it using a ragfork, then burn it. You should never mow or cut ragwort down as it just makes it grow back faster.

2. Foxglove

This flowering plant can grow up to 2 meters tall and will produce purple/pink flowers in hanging tubular shapes, usually between June to September. This is a very poisonous plant to horses and just 100g of it can be fatal, whereas other symptoms may include: contracted pupils, convulsions and breathing difficulties. Symptoms will usually occur within a few hours.

Luckily, many horses won’t eat foxglove when it’s growing but may do so if it’s chopped in hay, and the risk of poisoning is still present even when it’s dried or dead. Always keep horses away from areas when foxglove grows, and it should be removed from grazing land straight away.

3. Deadly nightshade

Deadly nightshade is a flowering plant that can grow up to 1.5 meters tall and produces flowers that are a dull brown or purplish colour and shining blackberry fruits. Despite the name, the plant is seldom fatal when ingested, but it can still cause serious harm as it releases atropine alkaloids into the body. Symptoms can include unconsciousness, pupil dilation, blindness, disorientation and convulsions.

Most horses dislike the taste, but it’s still important to remove the plant from your paddock via pulling it up or digging as all parts of the plant are toxic, especially the stems and leaves.

4. Acorns

Where oak trees are usually harmless for most of the year, come autumn when they drop their acorns, this turns into a very poisonous tree. One of the biggest issues with acorns is that horses find them particularly palatable, and many will readily eat them. When consumed in large quantities, symptoms can include colic and acorn poisoning.

If there’s an oak tree in your horse’s paddock, collect the acorns up, fence the tree off or move them into a different field during the autumn.

5. Yew

This evergreen tree or hedge is very common as garden boundaries, but the fallen leaves and red berries are highly poisonous to horses as they contain the toxin Taxine. Only 0.5kg of yew can be fatal and symptoms may involve: muscular trembling, uncoordinated movements, collapse and breathing that sounds like groaning. However, be aware that sometimes the only symptom may be collapse.

Be cautious of any yew being blown into your horse’s field or cuttings being dumped as yew is still toxic even when it’s dead. When it’s fresh, it’s quite bitter tasting so they won’t usually eat it unless other food sources are short.

6. Laburnum

Laburnum trees produce bright yellow drooping flowers which may look pretty, but they’re pretty deadly to horses. This is because the tree contains the toxin cytisine and it’s found in all parts of the plant, but the seeds are particularly toxic. Symptoms of poisoning from laburnum may involve colic, diarrhoea, drowsiness, excessive salivation, fits, collapse or even coma.

As with many other plants poisonous to horses, laburnum has a bitter taste, so they usually won’t eat it if other food sources are available. However, it’s still very important to keep horses away from areas where it grows and it’s best to fence it off to prevent access.

7. Privet

Privet is another very common garden shrub, so watch out for neighbours’ hedges or cuttings. Fence privet hedges off if they’re within access of your field and be cautious of people dumping cuttings into your field. Box privet is the most dangerous and even small quantities can be fatal to horses.

8. Ivy

Ivy is a common leafy plant with deep green, triangle-shaped leaves on vines. This poisonous plant to horses contains the toxins triterpenoid saponins and polyacetylene and can cause reactions such as diarrhoea, colic, irritated skin around the mouth, loss of appetite and dehydration. Death from ingesting ivy is rare and it’s seldom eaten as it doesn’t taste very good, but still may be consumed if forage is scarce. Keep horses away from areas where ivy grows and if you find any in their paddock, remove it as soon as possible.

More common poisonous plants to horses in the UK

• Alsike clover
• Bluebells
• Bracken fern
• Buttercups
• Charlock
• Cherry trees
• Curly dock leaves
• Daffodils
• Hawkweed
• Hemlock
• Horse chestnut tree
• Horsetails
• Larkspur
• Laurel
• Lily of the valley
• Maple trees
• Meadow saffron
• Monkshood
• Mistletoe
• Pear trees
• Pigweed
• Pyracantha
• Ragweed
• Rhododendron
• John’s Wort
• Sycamore
• Wisteria

It’s very important to practice good pasture management and remove any plants that are poisonous to horses as soon as you can. If this isn’t possible, horses should be moved to alternate pastureland as it’s better to be safe than sorry.

If you suspect your horse has eaten something poisonous, contact your vet as soon as possible as speedy treatment can make all the difference.

Looking for more advice on caring for your horse? Check out our guide on common equine digestive issues, next.