Are citronella plants poisonous to horses?

Asked February 12, 2014, 7:08 AM EST

A past student that's working overseas on a tropical island asked me this & I can't find an answer. A gardener planted some just outside the paddocks and she's wondering-
1) will they eat them- are they palatable?
2) if they do, just how toxic are they?
3) what would be the signs of poisoning by citronella?

Clinton County New York

1 Response

There are actually several different plants which may be referred to as the citronella plant. A variety of geranium "Pelargonium citrosum" can be called a citronella plant, as well as some others that go by "mosquito plant".

Oil of citronella is extracted from the tropical citronella grasses "Cymbopogon nardus" and "Cymbopogon winterianus." Since you mention a tropical climate, my feeling is that is is one of these plants. Citronella includes the components citronellol and geraniol, which repel mosquitoes.

There is very little information available about the toxicity of these plants when ingested by horses, so unfortunately we do not have a definitive answer for you. We know that geraniol is toxic to cats and dogs, and is used as an ingredient in natural fly sprays for horses. Keep a close eye on horses who may be within reach of the citronella plants and monitor for any unusual behavior or symptoms. You can also monitor the citronella plants to see if they have been nibbled or eaten in large quantities. It may be worthwhile to ask a veterinarian who practices in a tropical region, who may be more familiar with the plant.

Laura Gladney
Rutgers University