Mandevilla, also known as rock trumpet, is a popular flowering vine prized for its glossy foliage and showy, trumpet-shaped blooms in vibrant shades of pink, red, and white. Gardeners in areas with high wildlife populations often need plants that can withstand browsing pressure. Understanding how this tropical vine interacts with local deer populations is a frequent concern for those maintaining a colorful landscape.
Is Mandevilla Deer Resistant?
Mandevilla is widely regarded as a deer-resistant plant, making it a favorable choice for gardens near wooded areas or high deer activity. Deer rarely choose to eat it when more palatable food sources are available in the landscape. The plant’s natural characteristics place it low on the preference list for most foraging animals. While no plant is completely deer-proof, especially under extreme conditions like drought or deep winter snow, Mandevilla is seldom severely damaged. Gardeners should consider it a low-risk option.
Why Mandevilla Is Generally Avoided
Deer avoid Mandevilla primarily due to the plant’s internal chemical composition, which acts as a deterrent. The stems and leaves contain a thick, milky white sap, or latex, that oozes out when the plant tissue is broken. This latex is unpalatable to deer and can cause mild gastric distress if consumed in sufficient quantity.
Mandevilla belongs to the Apocynaceae family, known for containing various toxic compounds, including saponins. These unpleasant effects teach foraging deer to bypass the plant in favor of vegetation that is easier to digest. This inherent toxicity provides a built-in defense mechanism.
Identifying True Deer Damage
If a Mandevilla plant shows signs of being eaten, it is important to confirm that a deer is the actual culprit before implementing deterrence measures. Deer lack upper incisors, which results in a characteristic feeding pattern. When a deer browses, it tears the plant material against its lower teeth and upper dental pad, leaving ragged, rough, or unevenly shredded stems and leaves.
Damage caused by deer is typically found higher up on the plant, often between one and six feet above the ground, targeting tender new growth and branch tips. By contrast, small mammals like rabbits possess sharp incisors that create a clean, precise, 45-degree angled cut on the stem. Rabbit damage is confined to low-growing vegetation, usually within a few inches of the soil line.
Practical Strategies for Deterrence
If deer are observed repeatedly browsing the Mandevilla, external protective measures may be necessary.
- Physical barriers: Installing an eight-foot-tall fence is the minimum height required to prevent deer from jumping.
- Temporary exclusion: Netting or cages can be placed around individual plants, particularly when the Mandevilla is newly planted and vulnerable.
- Repellent sprays: Employ various scent-based or taste-based repellent sprays to make the plant less appealing. Commercial products often contain ingredients like putrefied eggs or animal blood.
- Scent deterrents: Using highly scented bar soaps hung near the plants is a simple method, as the strong fragrance can confuse a deer’s sense of smell.
These repellents must be reapplied frequently, especially after rainfall or new growth emerges, to maintain effectiveness.