Calla lilies (Zantedeschia aethiopica) produce showy white flowers and are hardy in U.S. Department of Agriculture (USDA) plant hardiness zones 8 through 10, depending on the cultivar. Although popular as decorative plants outdoors and as houseplants indoors, they are toxic to cats if they are ingested. Protect your curious kitty from the poisonous effects of calla lilies by keeping the plants out of the reach of the feline's paws.
Calla lilies, also referred to as arum lilies, often produce eye-catching white flowers, but some cultivars produce flowers in varying colors, including yellow, orange and red. The flower of a calla lily consists of a white spathe, which is up to 10 inches long, surrounding a yellow, finger-shaped spadix, which sits on a green stalk that is 2 to 3 feet in height. Calla lilies grow best in moist to wet soil in a location that receives full sun exposure or partial shade. The rhizomatous plants are considered marginally aquatic and can grow along the edges of ponds or other water gardens. Calla lilies bloom in late spring to midsummer.
If ingested by a cat, calla lilies are toxic because all parts of the plants contain chemicals called insoluble calcium oxalates, according to the American Society for the Prevention of Cruelty to Animals' website. The plants' bulbs contain the highest concentration of these toxic crystals. When a cat bites into a calla lily plant, the sharp calcium oxalate crystals are released, shooting out of the calla lily and penetrating the tissue of the cat's mouth, throat and gastrointestinal tract, resulting in pain and irritation of those areas. After biting and ingesting the plant matter, the cat drools, vomits and has a lack of appetite, according to the Pet Poison Helpline website. The cat also may paw at its mouth due to oral pain.
If your cat nibbles on calla lilies, take the cat to a veterinarian. Most poisoning symptoms are usually mild because ingestion of the calla lily plant matter causes immediate irritation of the skin and mouth tissue. Unfortunately, sometimes the tissue damage caused by calcium oxalate crystals results in severe swelling of the tongue, lips, mouth, throat and/or upper airways, according to Pet Poison Helpline. The swelling can impede the cat's breathing and ability to swallow. The veterinarian will rinse the cat's mouth and facial areas affected by calcium oxalates and will administer anti-inflammatory medications to relieve swelling. She also may give the cat medication for pain and intravenous fluids to prevent dehydration.
Unlike true lilies (Lilium spp.), ingested calla lilies don't cause kidney failure in felines, according to a Pet MD website article. True lilies are hardy outdoors in USDA zones 3 through 10, depending on the species, and also are grown as houseplants. Peace lilies (Spathiphyllum spp.) are hardy outdoors in USDA zones 11 through 12 but are also popular houseplants and look similar to calla lilies. They contain the same toxins as calla lilies because they are in the same family, Araceae. Place all lilies in areas that your cat can't access, or keep them out of your home and provide your cat with a screened-in, outdoor enclosure, away from potentially poisonous plants outside.
- American Society for the Prevention of Cruelty to Animals: Calla Lily
- University of California-Davis: Safe and Poisonous Garden Plants
- Missouri Botanical Garden: Zantedeschia Aethiopica (White Calla Lily)
- Pet MD: Lily Poisoning in Cats
- Bayer Advanced: Are Your Houseplants Poisonous?
- Pet Poison Helpline: Calla Lily and Cats
- Fine Gardening: Genus Lilium (Lily)
- Pacific Bulb Society: Zantedeschia
- Pet Poison Helpline: Oxalates (Insoluble)
- Infovets.com: Toxic Substances, Plants and Animals
- Hemera Technologies/PhotoObjects.net/Getty Images