Winterberry Plants & Cats


Winterberry plants, as their name suggests, provide brilliant red berries that remain on the tree all winter. For home growers with cats, however, this vivid fruit display poses a significant threat to pets. Familiarize yourself with the winterberry plant for vigorous growth, and take note of the particulars to protect your pets from harm.

Ornamental Description

The winterberry (Ilex verticillata) is a deciduous holly shrub with female plants that display vivid red berries throughout the cold months of winter, according to the Clemson University Extension. The winterberry produces green foliage that turns a light yellow hue during autumn and the plant grows to a height of 6 to 9 feet, according to the University of Illinois Extension.

Proper Care

Plant winterberries in locations that offer full sun exposure to partial shade. Winterberry plants prefer moist, well-drained soil; tolerances include alkaline soil and wet sites. This holly plant, unlike other Ilex species, is often found thriving in bogs, according to the Clemson University Extension. For best growth, plant in USDA Hardiness Zones 4 to 9, according to the University of Illinois Extension.

Pet Toxicity

The winterberry holly plant, along with English holly, European holly, Oregon holly, inkberry and American holly, is toxic to cats as well as dogs and horses, according to the American Society for the Prevention of Cruelty to Animals. A toxic substance in winterberries called saponin is similar to caffeine and is toxic to animals. A protein called ilicin found in winterberry is also toxic. Though the entire plant poses a threat, winterberry plant parts are not tasty to animals so the severity of poisoning is usually not extreme. Toxic reactions include gastrointestinal distress like diarrhea, vomiting and nervous system depression.


Winterberry cultivars include, but are not limited to, 'Afterglow', a winterberry with orange-red fruit and a height of 10 feet. 'Red Sprite' reaches up to 5 feet tall and displays large, vivid red fruit. 'Winter Gold' produces yellow fruit and reaches 7 feet in height. 'Winter Red' yields large amounts of vibrant red fruit and grows to a height of 9 feet, according to the University of Illinois Extension.


Winterberry plants are susceptible to wood rots and decays. Fungal pathogens invade winterberries and develop into infections. This type of problem often displays fruiting bodies or fungal growths on trunks as as symptom of the rot and decay occurring on root systems and heartwood, according to the University of Illinois Extension. Examine your winterberry on a regular basis; your winterberry may die or collapse due to disease. If your tree displays disease symptoms, identify the present infection and employ control methods; when in doubt, contact your local county extension agent for assistance. Additionally, always sanitize pruning tools during and after use to prevent spread of fungi. Create clean cuts to prevent formation of wounds through which fungi enter.

Keywords: winterberry plants cats, winterberry pet toxic, winterberry holly plant

About this Author

Tarah Damask's writing career, beginning in 2003, includes experience as a fashion writer/editor for Neiman Marcus, short fiction publications in "North Texas Review," a self-published novel, band biographies, charter school curriculum, and articles for eHow. She has a love for words and is an avid observer. Damask holds a Master of Arts in English and creative writing from the University of North Texas.