If 50 years of perfumed spring air aren't enough to make peonies (Paeonia spp.) a garden essential, the long-lived plants' stunning floral displays certainly are. Clumps of glossy, green peony foliage continuing into the fall make striking backdrops for later-blooming plants. Unfortunately for animal-loving gardeners, so much perfection has its dark side in the form of an animal-toxic poison.

Peony flowers
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A bush of pink peonies.

Pets and Peonies Don't Mix

Garden or Japanese forest peonies (Paeonia lactiflora, Paeonia obovata) -- suitable for U.S. Department of Agriculture plant hardiness zones 3 through 8 -- and tree peonies (Paeonia suffruticosa, perennial in USDA zones 5 through 9) all love sunny spots and loose, moist soil. The problem is that many cats and dogs share those preferences, along with a desire to nibble on vegetation. In such situations, pets and peonies aren't a good mix. Horses are also susceptible to peony poisoning. Unless starving, however, they're much more likely to give the plants a pass.

Reducing the Risks

From the time peonies' shoots emerge in spring until their foliage dies back in fall, only supervised pets should have access to the garden. Caged peonies discourage digging and snacking. Provide cats with a distant garden corner, complete with sand-filled litter box, snacking grass, water and -- in USDA zones 3 through 8 -- perennial catnip (Nepata x faassenii). Periodically sprinkling coffee grounds around the peonies reinforces the "cats unwelcome" message. Spraying the plants with water and then sprinkling them with cayenne pepper deters both cats and dogs, according to the American Society for Prevention of Cruelty to Animals. Removing the water bowl for an hour after the animals taste the pepper helps get the point across.

Signs of Peony Poisoning

Dogs or cats ingesting large amounts the paeonol toxin in peony flowers, seeds, roots, bark or leaves may experience mild irritation of their oral tissues, vomiting, diarrhea and depression. Horses suffer gastroenteritis, or inflammation of the digestive tract. Because it's nearly impossible for them to vomit, peony poisoning in horses can be much more serious than it is in pets.

How to Handle Potential Poisoning

The first thing to do for a pet or horse found munching on a peony is to get it away from the plant as quickly as possible. With a damp cloth, clear as much material as possible from in and around the animal's mouth. Unless it's clear a dog has just swallowed part of the plant, don't induce vomiting. Never induce vomiting in a cat, cautions the Pet Poison Helpline. Don't wait for symptoms of poisoning to surface before calling your veterinary hospital or the Pet Poison Helpline for instructions. If advised to seek veterinary care, provide pieces of the peony as well as its botanical name. If a pet vomits on its own, bring along a sample in a sealed plastic bag.