Landscaping Plants to Avoid

Often, landscape plant choices are based on aesthetics and hardiness. However, with animals in the mix, plant toxicity is perhaps a more important aspect to consider. Even if owners plant trees, shrubs, and flowers well out the reach of domestic animals, the animals could still be exposed. Strong winds, storms, and flooding, for instance, can carry branches and other plant materials. Contractors might discard plant trimmings, unaware of how toxic some can be.

According to the University of Kentucky's College of Agriculture, some landscape plants should be avoided on horse farms or any place where animals may be exposed. The homeowner or contractor may want to consult a veterinarian or a veterinary toxicologist experienced with animal poisoning for more information. The list below is intended for use in the Bluegrass region of Kentucky and surrounding areas. It is by no means all-inclusive but includes some of the more common and important plants that could pose a toxic risk to horses, dogs and cats.

Trees to avoid on horse farms include: Red maple and other maples, wild cherry, black walnut, black locust, oak, Kentucky coffee tree, buckeye, golden chain tree, mimosa, persimmon, chinaberry, tung nut, and cycad palms.

Shrubs to avoid include: Japanese or other yew (Taxus) bushes, privet, common box, elderberry, Carolina allspice, choke cherry, serviceberry, buckthorn, fetterbush, laurel, and day-blooming Jessamine. Taxus bushes are especially toxic and ingestion of discarded Taxus hedge trimmings is a common cause of death in horses.

Flowering garden plants to avoid include: Delphinium, lily of the valley, foxglove, rhododendron and azaleas, lobelia, sweet pea, castor beans, bulbs such as autumn crocus, lilies, iris, hyacinth, amaryllis, and daffodils; poppies, morning glory, bleeding hearts, pieris, lantana, lobelia, ground cherry, angel's trumpet, periwinkle, monkshood, harebell, hibiscus, clematis, star-of-Bethlehem, bracken fern, rosary pea, baneberry, pheasant's eye, Lords and Ladies, begonia, butterfly weed and other showy milkweeds, yesterday today and tomorrow, caladium, diffenbachia and philodendron species, moonflower and other Datura species, sesbania, honeysuckle, may apple, and blue indigo.

Many weeds are toxic to animals. Some mulches also can pose risks to animals; avoid black walnut mulches and cocoa hull mulches in particular. Additionally, discuss risks of toxic plant exposure with neighboring property owners so they do not unintentionally poison your horses by discarding garden trimmings into your horse pastures.

This list is not all-inclusive and does not include important toxic plants that are not typically grown in the Bluegrass region (for example, oleander is an extremely toxic plant that causes many equine deaths in southern states but is not typically found in Central Kentucky). As with other toxicants, intoxication depends on exposure dosage. Consult with your veterinarian or a veterinary toxicologist to determine if your garden plant choices could pose a risk to horses or other animals.