What Plants Are Poisonous for Horses?

Poisonous plants have no place in a horse pasture. Horses usually avoid poisonous plants, but their instinct does not always protect them reliably. Poisonous plants can also get into the hay and cause poisoning.

How poisoning symptoms manifest themselves in horses, how you have to react and which poisonous plants there are, you can find out in our guide.

How do I recognize poisoning in my horse?

Poisoning in a horse can show itself in many different ways. It is crucial how much and what kind of poison the horse has eaten.

Some toxins take effect very quickly. The horses suddenly show severe changes. For example, their pupils dilate greatly, convulsions occur, breathing problems, disturbances in movement and in the digestive process occur. The animals become very restless or listless. They may sweat, salivate or tremble.

Other poisons, on the other hand, have a slow effect over a longer period of time – for example, because the animals ingest small amounts of poison continuously. Ulcers can form in the throat, the horses become emaciated and are tired and powerless.
What symptoms can occur in horses during plant poisoning?

strongly dilated pupils
strong thirst
excessive sweating and salivation
strong nervousness
altered breathing
difficulty swallowing
digestive problems (diarrhea, but also constipation)
circulatory problems and movement disorders
increased sensitivity to light
skin rashes or edema

Symptoms may occur singly or in combination. If your horse shows one or (probably) more of these symptoms, your horse may have poisoned itself. It may have eaten poisonous plants growing in the pasture or that were in its hay.

IMPORTANT:

You should always call the veterinarian if you suspect poisoning! Poisoning can cause acute circulatory failure and become life-threatening.

TIPS:

Carefully search the pasture for poisonous plants or examine the forage hay for poisonous ingredients. If you know which poisonous plant your four-legged friend may have eaten, the veterinarian can help him in a more targeted manner.

NOTE:

In addition to certain plants, certain foods are also toxic to your horse. You can find out which foods can be dangerous for your four-legged friend in our guide 10 absolutely taboo foods for your horse

Occurrence: Where are poisonous plants commonly found for horses?

Some poisonous plants are often found in wet pastures, areas adjacent to pasture or exercise, along roadsides or in forests. However, horses can also get poisoned by toxic ornamental plants on horse farms, for example. These include the yew hedge, the thuja hedge or the laburnum. Even if a hedge trim has not been disposed of carefully, it can endanger horses.

But it’s not only outside in the pasture, on a ride or in the yard that horses can ingest poisonous plants; danger also lurks in the stable when they eat hay. This is because some poisonous plants, such as autumn crocus or ragwort, are poisonous even when dried.
Poison in hay: How can I recognize poisonous plants in hay?
Recognize meadow saffron in hay

Even dried, you can spot meadow saffron quite easily. The leaves are beige to brown and resemble the leaves of tulips with their elongated shape. Their seed pods are usually cup-shaped and brown.
Recognize ragwort in hay.

Identifying dried ragwort in hay is very difficult. The plant dries and the stems and leaves lose their original color. The leaves of ragwort become very similar to the leaves of dandelion. When dry, the herb disintegrates easily, making it difficult to identify with certainty.

NOTE: Our guide “How much hay does my horse need?” informs you, among other things, about what quality characteristics you should also look for when feeding hay.

Help: What can I do if I suspect that my horse has been poisoned?

If you suspect that your horse is poisoned because of certain symptoms, you must call a veterinarian immediately and describe the symptoms. It can be life threatening if your horse has poisoned himself. The veterinarian will know if he needs to come immediately and what to do.
What can I do if my horse has eaten poisonous plants?

If you have observed that your four-legged friend has eaten poisonous plants and he (still) shows no or only weak symptoms, you should also contact your veterinarian. He will discuss the further procedure with you.

Treatment: What does the vet do if my horse has poisoning?

The veterinarian will treat depending on what symptoms the horse is showing and what type of poison it ate. He will primarily initiate symptomatic therapy, since there is often no antidote – even if it is clear which poison the animal has ingested.

The following measures/medications may be necessary:

Gastric lavage and emptying.
Using a nose-to-gut probe, the veterinarian can flush and empty the horse's stomach from nose to stomach. In this way, he removes toxin from the stomach and prevents it from going further into the intestines and being absorbed here. He can also introduce activated charcoal into the stomach through the tube, which binds the poison.
Circulation stabilizing drugs
Respiratory stimulating drugs
Anticonvulsant drugs
Intravenous fluid administration (dilutes the toxin; stabilizes fluid balance; helps excrete the toxin through kidneys)

Prevention: How can I protect horses from poisonous plants?

Find out about poisonous plants and search your horse’s pasture for them. If you find them, remove them thoroughly. Open areas in the pasture should be reseeded to prevent the growth of poisonous plants. You should also check the entire yard for poisonous plants and make sure that horses have no contact with them. It’s best to replace them with non-toxic ornamental shrubs. Also make sure that you feed your horses only hay of impeccable quality.

Overview of poisonous plants – what horses must not eat!

Normally horses do not eat poisonous plants, as they often contain bitter-tasting ingredients. Their instinct makes the animals steer clear of certain plants. However, you shouldn’t rely on this. In addition, most poisonous plants lose their characteristically bitter and thus unpleasant taste when they are dried. Then your horse will eat them with the hay or even if the plant has dried up bent on the meadow. Therefore, you should systematically remove the following plants from horse pasture and forage meadow.

NOTE: The lists do not claim to be complete!

Information about poisonous plants on meadow, pastures, forest and waysides

bracken (Pteridium aquilinum)

often spreads in masses along forest edges and bushes
up to two meters high
fronds 3 to 4 pinnate
toxic and carcinogenic
contains high levels of hydrocyanic acid glycosides and thiaminases, which cause central nervous system disorders in horses when ingested frequently

Adonis herb (Adonis)

poisonous buttercup
grows mainly on dry grasslands, preferably in warm and sunny places
between ten and 40 centimeters high
bright yellow or red, solitary and up to six centimeters large flowers
blooms between April and May
fruitlets form spherical head
when poisoned with the spring Adonis rose, the heartbeat slows down - even to a standstill
all above-ground parts of the plant are poisonous for horses

arum (arum)

carrion-like fragrant flower
green-white bracts and central bulbous inflorescence
blooms between April and June
leaves present only in spring
forms fruiting spike with bright red berries
occurs on nutrient-rich soils in shady locations
rare in Germany

Monkshood (Aconitum napellus)

deadly poisonous plant
effective poison: alkaloid aconitine in flowers, leaves and roots
mainly in mountainous regions near streams and springs
often cultivated in ornamental gardens
easily recognizable by its characteristic up to 150 centimeter high inflorescence
blue-violet to deep blue flowers between June and August

Foxglove (Digitalis)

in Germany three species: large-flowered foxglove, yellow foxglove and red foxglove
up to 200 centimeters high, characteristic inflorescences with purple or light yellow flowers
stems unbranched and felt-like hairy
between June and August up to 100 bell-shaped flowers per flower cluster
deadly fresh and dried even in small quantities
grows mostly in larger groups at waysides and forest edges
Poisons of foxglove are: Digitalin, Digitoxin and Gitatoxin; act on heart muscle

Spotted hemlock (Conium maculatum)

highly poisonous herb, which causes visual disturbances and paralysis up to respiratory paralysis
stems erect and many branched
often in groups on nitrogen-rich soils
especially on hedges, roadsides, fallow ground and fences
characteristically spotted stem up to 200 centimeters high
small, white flowers arranged in umbels
repulsive odor
dangerous for horses especially when dried in hay

Ground ivy (Glechoma hederacea)

also known as ground ivy
creeping or ascending in growth
up to approx. 60 cm high
grows on banks, forests, damp meadows and pastures
traditionally used in folk medicine
all parts poisonous for horses

Buttercup, sharp (Ranunculus acris)

also called buttercup
frequently occurring buttercup plant
up to 100 cm high
on meadow and pasture with rather moist, nutrient-rich soils
often present in large quantities
shiny yellow flowers between May and October
only poisonous when fresh, harmless when dried as hay

Autumn crocus (Colchicum autumnale)

contains deadly poison colchicine
mostly avoided in fresh state
dangerous when dried as a hay ingredient, toxins active here for years
grows on moist, nutrient-rich soils
characteristic purple and funnel-shaped flowers
late bloomer: flowers appear between August and November

ragwort (Jacobaea vulgaris)

also known as Jacob's ragwort
Compositae with characteristic yellow flowers
blooms between July and September
pinnately lobed leaves
often found in meadows and pastures
contains pyrrolizidine alkaloids which cause chronic liver poisoning
alkaloids not degraded even after preparation of hay and silage

St. John’s wort (Hypericum perforatum) –

also called spotted hay
occurs on meager pastures
up to 100 centimeters high perennial with yellow flowers between July and August
crushed flowers turn red
used by humans as a medicinal plant, but poisonous for horses
symptoms of poisoning resemble sunburn: redness, edema, lesions

Black henbane (Hyoscyamus niger) –

belongs to the nightshade family
one of the oldest known poisonous plants
usually grows on nitrogen rich soil
needs a lot of sun and warmth
causes paralysis up to respiratory arrest
dangerous fresh and dried as hay

Belladonna (Atropa belladonna)

belongs to the nightshade family
contains highly toxic alkaloids as well as tannins and flavonoids
up to 150 centimeters tall, with violet-colored flowers from June to August
fruits: up to 1.5 centimeters in size and black in color
often grows in forest clearings and forest slash areas
Poisonous substance atropine is formed when the plant dries
paralysis symptoms up to respiratory arrest

Marsh horsetail (Equisetum palustre) –

perennial herbaceous plant
usually 10 to 60 cm high, rarely 100 cm
on wet meadow, fen, banks
for horses especially the thiaminase is poisonous => staggering of the animals
in cattle palustrine leads to lower milk yield and paralysis

Other poisonous plants

In addition to the listed poisonous plants in meadow, pasture and roadsides, some trees and shrubs are also poisonous to horses. These include common deciduous trees such as black locust (false acacia) or oak, but also the highly poisonous yew and the ornamental shrubs laburnum or boxwood.