When planning a garden, a common question is whether the culinary herb basil will fall victim to hungry deer. Basil is considered deer-resistant, meaning it is not a preferred food source. However, deer are opportunistic eaters, and the level of protection basil offers can vary based on environmental conditions and the availability of other forage.
Deer’s Relationship with Basil
Basil is not a primary target for deer due to the strong essential oils and pungent flavor profile contained within its leaves. The aroma acts as a natural deterrent, as deer generally avoid plants with intense or bitter tastes. Despite this resistance, basil is not entirely deer-proof.
The plant’s moderate resistance means that under high deer pressure or during periods of food scarcity, such as drought, deer may still sample the leaves. Young, tender growth is particularly vulnerable to browsing because it is less fibrous and has a lower concentration of deterrent oils. Deer damage to basil is characterized by ragged or torn leaf edges, resulting from deer tearing the vegetation since they lack upper incisors.
The specific chemical compounds in basil, such as linalool, eugenol, and estragole, are examples of plant secondary metabolites that contribute to its unpalatability. These oils signal to the deer that the plant may be unpleasant. While a deer may take a bite, the strong flavor often causes them to abandon the plant quickly in favor of a more palatable food source.
Why Deer Avoid Aromatic Plants
Deer rely heavily on their acute sense of smell to locate food and detect potential danger. Their olfactory system allows them to process the complex chemical signals emitted by plants. This reliance on scent means that volatile organic compounds (VOCs) play a significant role in their foraging decisions.
Plants that produce strong VOCs, particularly terpenes, are often avoided because these compounds signal a potentially bitter or indigestible meal. The aversion to certain plant chemistry is an evolutionary mechanism, as strong flavors or odors often indicate a defense compound that could cause digestive upset.
Plants with fuzzy, tough, or spiky textures are also generally avoided, as these physical characteristics make chewing less desirable. This combination of strong scent, pungent taste, and texture creates a sensory barrier that steers deer toward less chemically defended vegetation.
Protecting Vulnerable Garden Areas
If deer browsing remains an issue, implementing physical and chemical deterrents offers the highest level of protection. The most reliable method is a permanent, vertical fence constructed of woven wire or mesh that stands at least eight feet tall. Since adult deer can easily jump fences up to seven feet high, the extra height is necessary.
For areas where a permanent tall fence is impractical, a temporary or angled electric fence is an effective alternative. Even a shorter fence of about four feet can deter deer from small, confined garden plots because they fear becoming trapped.
Another strategy involves using commercial taste- and odor-based repellents, which typically contain putrescent egg solids or garlic oil. These repellents work by making the plants smell or taste repulsive, but they must be reapplied regularly, especially after heavy rain or during new growth.
Companion Planting
A strategic planting approach, known as companion planting, also enhances protection. This involves placing highly aromatic plants like lavender or rosemary around the perimeter of the garden. This creates a powerful scented border that deer often avoid crossing to reach more desirable plants inside.