JILL RICHARDSON, DVM

It’s finally summer, but can all of the pretty flowers in bloom spell trouble for you and your kitty? Make sure to check all fresh and garden flowers to make sure that they are not dangerous — or deadly — for your pets.

There are hundreds of plants that may be poisonous, and even nonpoisonous plants can cause mild stomach upset if they are ingested in quantity. The following are some of the most dangerous plants that you should make sure to keep away from your pets.

Lilies

Easter lilies (Lilium longiflorum), tiger lilies (Lilium tigrinum), rubrum lilies or Japanese showy lilies (Lilium speciosum and Lilium lancifolium), and various day lilies (genus Hemerocallis) are highly toxic to cats. These beautiful and colorful plants are grown as ornamental flowers and are commonly found in bouquets and flower arrangements. While the exact toxic component is unknown, cats appear to be the only species sensitive to its deadly effects. A cat licking or chewing on the plant may develop kidney failure that could be fatal. Even small ingestions, such as a few bites on a leaf or ingestion of pollen, can be deadly.

Rhododendron

Rhododendron species contain a toxic substance known as grayanotoxin. Grayanotoxins can be very dangerous if the plants containing it are ingested. This type of poison causes stomach upset, but it can also affect the heart rate and nervous system. As few as two leaves may cause dangerous toxicity. A common plant found in this family is the azalea, which is often used as an ornamental plant.

Plants That Contain Cardiac Glycoside

Cardiac glycoside is a poison; the most commonly recognized is digitalis, which is sometimes used in medication to treat cardiovascular disease in people and pets. Plants that contain this type of poison are highly toxic because they can cause life-threatening damage to the heart. Examples of these types of plants include oleander (Nerium oleander), lily-of-the-valley (Convallaria majalis), foxglove (Digitalis purpurea), certain milkweeds (Aesclepias spp.) and squill (Virginea maritime). All parts of plants that contain cardiac glycoside are toxic, and even small amounts can be deadly.

Castor Beans (Ricinus communis)

The castor bean plant is used as a decorative plant and as jewelry, and sometimes the oil (castor oil) from the plant is used medicinally. The toxic ingredient in this plant is ricin, which is one of the most potent toxins known to man. Castor bean seeds contain the highest concentration of ricin in the plant and are most commonly associated with poisoning. The beans must be crushed to release the toxin, but even small amounts of ricin can be fatal.

Cycad Palms (Cycas, Zamia)

These ornamental plants are found naturally in areas of sandy soil, like in Texas, Florida and California. This plant is also becoming a popular bonsai-style houseplant. Cycasin is the toxic component of this plant. Cycasin is found throughout the plant, although it is more concentrated in the seeds. This toxin can cause severe liver failure if it is ingested by a cat. Ingestion of one or more seeds has resulted in severe symptoms and even death in pets.

Yews, Taxus Genus

Many types of yew bushes are used in landscaping, and they also grow naturally. The toxic ingredient in these bushes is taxane. Most cases of poisoning from yew bushes typically result from trimmings fed to grazing animals; however, a bored cat may chew on the bush. In cattle, horses, and goats, the toxic ingredient results in heart failure and sudden death. In dogs and possibly in cats, the animal usually experiences seizures following its ingestion.