Green Isn’t Always Healthy – Plants You & Your Horse Should Avoid

Green Isn’t Always Healthy – Plants You & Your Horse Should Avoid

Wednesday, August 24th, 2011

Green isn’t always healthy – Plants you & your horse should avoid

Every horse owner should know what is safe for their horse to eat, and what isn’t. After all, we don’t causally feed our children glasses of window cleaner, do we? It’s easy to forget or overlook the fact that there are plants and vegetation that our horses shouldn’t be eating, because apart from any hard feed you give them, they just eat grass – right?

Wrong. Horses are curious animals who like to try out pretty much anything. If it reaches into their paddock, you can bet that at some point, they’ve checked it out to see whether it’ll taste good. Thankfully, horses are also pretty smart – they generally know when not to eat something. However, mistakes do happen.

There are plants and trees that horses will eat, that will either seriously harm them or kill them. As if that weren’t enough of a worry, there are several factors that can influence the toxicity of the plant – it’s stage of growth (some plants are only poisonous at certain stages of their life span), the season (some plants are only poisonous at certain times of the year), the fertilizer used (some fertilisers can increase or flush the level of toxicity within the plant) and the part of the plant eaten are just a few of several factors which can affect how poisonous the plants are, and even the likelihood of your horse trying them out.

Now the types of plants will obviously vary country to country, state to state – but here are a few common devils that you will want to be on the lookout for.

Paterson’s Curse

Native to the Mediterranean region, this weed is the literal curse of Australian paddocks. Paterson’s will literally take over paddocks, especially those where little vegetation grows otherwise, such as pastures affected by drought or fire. It will grow just about anywhere, and all parts of the plant are toxic – even when dried and seemingly dead. Don’t graze horses in paddocks with Paterson’s Curse, and make sure you check your hay for the weed.


Most variations of maple are poisonous to horses – sadly, most horses also find the leaves tasty! Fresh leaves are relatively safe, but dead, fallen leaves can be noxious. They can remain dangerous for several weeks after they’ve fallen from the tree, and can severely affect the red blood cells.


Nightshades are related to the tomato plant, and can be deadly. These plants can cause abdominal pain, diarrhea, loss of appetite, weakness, trembling, progressive paralysis and death.

St John’s Wort

St John’s may be seen as a healing agent for humans, but it actually causes photo sensitization in horses, thanks to a pigment they contain which is absorbed by the body and activated by sunlight. If your horse eats the Wort, it can develop a condition where patches of light coloured skin become ultra-sensitive to sunlight, and burn very easily.

There are also several household products that we don’t think twice about, but which should be kept far from our horses. Avocadoes, onions, potatoes, persimmons, & rhubarb are all highly poisonous to horses and should not be fed to them under any circumstances.

Ask your vet or check out your local agriculture store for information on what plants to avoid in your area, and how to treat them. Remember, prevention is better than cure, so if you’re in doubt, always act on the safe side, and move your horse to another paddock, remove the plant by hand, or rope it off in a way so your horse can’t reach it.

Ellie Fraser