Pittosporum is a popular genus of evergreen ornamental shrubs, valued for its dense, attractive foliage. They are a common choice for hedges and foundation plantings in many mild climates. Gardeners need to consider the vulnerability of these plants to the local deer population, which can quickly defoliate a prized specimen.
The Deer Resistance Profile of Pittosporum
Pittosporum is generally categorized as deer-resistant, a designation that is important to distinguish from deer-proof. This classification means the plant is not a preferred food source and will typically be avoided if more palatable options are available. University sources often list this shrub as “seldom severely damaged” or “rarely damaged” under moderate deer pressure. While browsing damage is uncommon, it is still possible, particularly when deer populations are high or food is scarce.
Plant Characteristics That Deter Deer
The plant’s natural defenses provide a biological basis for its resistance to browsing. The primary deterrent is the texture of the leaves, which are often thick, robust, and leathery, such as those on Pittosporum tobira. Deer prefer tender, soft foliage, making the coarse leaves of established Pittosporum unappetizing.
Another factor is the aromatic compound content in the foliage. Many varieties, including Pittosporum tenuifolium, release a strong, pungent odor when the leaves are crushed. Deer rely on their sense of smell to evaluate food sources, and these strong scents signal that the plant is not a desirable meal.
Environmental Factors Affecting Consumption
The deer-resistant nature of the plant can be overcome by external factors. The most significant variable is the availability of alternative food sources, especially during environmental stress like drought or harsh winter weather. When preferred vegetation is unavailable, deer will eat almost any plant to survive.
Local deer population density also increases browsing pressure. High numbers of deer increase competition for food, forcing animals to experiment with less palatable plants. Additionally, the age of the plant matters; new and tender growth on young Pittosporum is much more vulnerable than the established, woody growth of a mature shrub.
Protecting Pittosporum in High-Traffic Areas
Gardeners dealing with high deer traffic can take steps to protect their plants. Strategic placement is effective, involving planting Pittosporum closer to high-activity areas of the home where human presence deters deer. Avoid placing them along common deer travel corridors or near dense woodlots where deer feel secure.
For newly installed shrubs, temporary physical barriers provide protection during the vulnerable establishment phase. Individual plants can be shielded using wire mesh cylinders or small netting cages. These barriers should be removed once the plant is established and the growth has matured into the tougher, less appealing texture.