If it is green, leafy and in the general area of your barn, a horse is going to decide to eat it. While most horses will not eat significant amounts of toxic plants if they have other roughage options, it is best not to plant any potentially toxic plants anywhere your horse may reach it. Consuming toxic flowers and shrubs can cause a horse to colic, have diarrhoea, experience neurological problems and even die.
Plants and Toxicity
Plants develop varying levels of toxicity as a natural defence against animals, such as horses. Some plants are universally toxic, while others become toxic under specific conditions such as drought, mineral imbalances or over-watering. Some plants only become toxic after the leaves wilt or if the horse consumes a specific part of the plant. Ornamental flowers and shrubs are generally not considered a good choice for horse barn greenery. Barn owners need to thoroughly research every plant they consider planting on their property before planting it.
The American Society for Prevention of Cruelty to Animals features a 269-page list of horse-safe plants on their website. Some of the more popular flowering plants include a variety of daisies, the African violet, achira, blooming Sally, blue bead, bottle brush, brides bonnet, Brazilian orchid, butterfly ginger, cape marigold, crape myrtle, creeping zinnia, pansies, Easter lily and others. The downside of many horse safe flowers is that horses will eat them, so be prepared to have your horse safe flowers consumed if the horses have access to them.
Horse-safe shrubs vary by region. However, speckled alders and various forsythias are considered safe for horses. Make sure any plant you are thinking about purchasing is considered horse safe before planting. Even if a plant is not considered toxic, it does not mean that it will not make your horse sick if it consumes large amounts of it. Even safe plants can upset a horse's digestive system if consumed in copious amounts.
Plants That Are Not Safe for Horses
The following plants are considered to be toxic or have parts that are toxic to horses and should never be planted in your barn area: oak trees, buttercups, azaleas, cherry trees, peach trees, plum trees, mountain laurel, cockleburr, stinkweed, oleanders, elderberries, locust, horsetail, alsike clover, laurel cherry, horse chestnut trees, holly, milkweed, black walnut, bracken fern, death camas, nightshade, buckeye trees, rhododendron, pokeweed, potatoes, tomatoes, avocados, onions, ergot, larkspur, lupins, sagebrush, yellow star thistle, hemlock and poison hemlock, St. John's wort, foxglove, tansy ragwort, wild blue flax, red maple trees, tall fescue and yew trees and bushes.