Rhododendron
Rhododendron spp.
Horse
Severe
Any suspected ingestion is an immediate veterinary emergency. A very small quantity (0.2% of the horse's weight, i.e, less than 1 kg of leaves) is lethal.
Equio informs, it does not diagnose. When in doubt, call your vet.
What to do now
- Antidote
- No specific antidote. Intensive symptomatic and supportive treatment (activated charcoal, enemas, fluid therapy, cardiac and respiratory monitoring).
- Time to signs
- 15 minutes to a few hours
- Prognosis
- Grave. Death from respiratory arrest can occur within hours.
- Absolute veterinary emergency.
- Activated charcoal.
- Gastric lavage.
- Atropine (to restart the heart).
- Do not stress the animal.
Its ID card
- Height
- 0.5 m – 6 m
- Flowering
- Spring (April to June, depending on species and region)
- Toxic parts
- Entire plant (leaves, flowers, nectar).
- Toxin
- Diterpenes (Grayanotoxins)
- Habitat
- Parks, ornamental gardens, acidic soils (heathland), mountain forests.
- Soil indicator
- Very acidic soils (heathland), shaded.
- Regions
- Europe, North America, Asia
- In hay
- Yes — stays toxic once dried
- Palatability
- Avoided when growing. Often consumed due to lack of grass or in garden waste.
When the risk rises
All year round (evergreen leaves).
Spotting it in the field
Oleander (leaves are somewhat similar). — smell : odorless
- Shrub with persistent foliage.
- Large, leathery, dark green leaves.
- Large clusters of very colorful flowers (pink, red, purple, white) in spring.
Signs to watch for
Acute toxicity
Dose : Less than 1 kg of fresh leaves for a 500 kg horse.
- Hypersalivation (heavy drooling)
- Vomiting (unproductive efforts in horses)
- Very slow heart rate (bradycardia)
- Extreme weakness, recumbent horse
- Respiratory distress
Who is affected
Other species : Extremely toxic to sheep, goats, dogs. Rhododendron honey is even toxic to humans ('mad honey').
In pregnant mares : lethal for both the mother and the fetus.
Getting rid of it
Method : Uproot the entire plant, including the roots, and destroy it by burning or deep burial. Wear gloves when handling the plant.
- Remove the plant from pastures and the vicinity of paddocks.
- Carefully monitor horses in areas where rhododendron is present, especially during periods of grass shortage.
- Avoid discarding garden waste containing rhododendron in areas accessible to animals.
Frequently asked questions
Can Equio identify Rhododendron from a photo?
It can help organize visual clues, but plant identification must remain cautious when horse health is at stake.
Is Rhododendron dangerous in hay?
This entry flags hay vigilance. Isolate suspicious forage and ask for professional advice if exposure is possible.
This page is informational. If ingestion is likely, if signs appear, or if the horse is fragile, contact a veterinarian immediately.