Calla lilies (Zantedeschia) are popular garden plants prized for their elegant, trumpet-shaped blooms and glossy foliage. For gardeners dealing with deer browsing, the answer is straightforward: generally, no, deer do not eat them. These plants are classified as deer-resistant, making them a valuable addition to landscapes frequently visited by wildlife. Their natural aversion stems from undesirable properties built into the plant’s structure.
Why Calla Lilies Are Deer Resistant
Calla lilies possess characteristics that deter deer from consuming them. Their taste is immediately unappetizing to browsing animals. Deer typically select plants that are tender, smooth, and mildly sweet, making the tough, leathery leaves and stems of the calla lily a poor choice.
The plant’s natural toxicity acts as a powerful deterrent. Deer have a highly sensitive sense of smell and taste, allowing them to quickly detect bitter or irritating compounds. This unpleasant sensation upon initial sampling teaches the deer to leave the plant alone, often after only a single bite.
The Mechanism of Calla Lily Toxicity
The deer resistance in calla lilies results from a specific internal defense mechanism. All parts of the Zantedeschia plant contain insoluble calcium oxalate crystals. These microscopic structures are shaped like tiny needles, known as raphides, and are stored in specialized cells throughout the tissue.
When a deer chews the leaf or stem, these cells rupture, ejecting the sharp raphides into the animal’s mouth and throat tissue. This physical penetration causes an immediate, intense burning sensation and irritation to the mucous membranes. The mechanical irritation is amplified by the simultaneous release of proteolytic enzymes, which contribute to an inflammatory response. This painful reaction ensures the deer abandons the plant quickly.
Exceptions to Deer Resistance
While calla lilies are effective at resisting browsing, no plant is considered absolutely deer-proof. Resistance can be overcome by environmental and population pressures that alter feeding behavior. During drought or late winter when natural forage is scarce, deer become less selective and may sample plants they normally avoid.
High local deer population density increases browsing pressure on all available vegetation, including resistant species. Young, tender growth on newly emerging calla lilies may be more vulnerable, as the full concentration of defensive compounds may not be developed. Even then, deer typically only sample the plant before moving on to less irritating food sources.
Simple Methods for Deterring Deer
For gardeners who experience browsing despite the plant’s natural defenses, combining methods is the most effective strategy for deterring deer. Physical barriers are the most reliable long-term solution, though they require an investment. A fence must be at least seven to eight feet tall to prevent a motivated deer from jumping over it.
Alternatively, a simple, low-cost barrier can be made using a fishing line strung between stakes around the garden perimeter. The nearly invisible line spooks deer when they brush against it, as they cannot see what is stopping them. Applying scent or taste repellents to the foliage can also be effective, but these must be routinely reapplied, especially after rain or new growth. Many commercial and homemade sprays utilize foul-tasting ingredients like eggs, garlic, or hot pepper to deter browsing.