Deer resistance in plants is not about immunity but rather about a plant possessing certain characteristics that make it unpalatable or less appealing to deer. These traits are evolutionary defenses developed by plants to deter herbivores. The primary factors include strong fragrances, bitter or toxic sap, fuzzy or tough textured leaves, and thorny stems. Plants that are highly nutritious, have tender new growth, or are easily accessible are often prime targets for foraging deer. It is crucial to understand that "deer resistant" is a relative term; a hungry deer will eat almost anything, especially in winter when preferred food sources are scarce.
Peonies (Paeonia spp.) are generally considered to be deer-resistant plants, and this classification stems from their specific botanical makeup. The most significant deterrent is the presence of paeonol, a compound found particularly in the bark of tree peonies and the roots of herbaceous varieties. This compound has a bitter taste and is unappealing to deer. Furthermore, the foliage and flowers of many peony varieties have a slight fragrance and a somewhat coarse, sometimes leathery leaf texture that deer tend to avoid when more delectable options are available. Unlike hostas or tulips, which are like candy to deer, peonies are rarely a first-choice meal.
While peonies are naturally resistant, certain conditions can make them vulnerable. The most significant risk occurs in early spring when the plant sends up its new, red shoots. These emerging stems are tender, succulent, and may not yet have developed the full concentration of bitter compounds, making them a potential target for curious or hungry deer. This is the period of highest vulnerability. Additionally, extreme environmental pressures, such as a harsh winter, drought, or a local overpopulation of deer that has depleted their natural food sources, can lead them to sample plants they would normally avoid, including peonies.
For gardeners in areas with high deer pressure, relying solely on a plant's natural resistance is not always sufficient. A multi-layered approach is most effective. Physical barriers are the most reliable method. Installing a tall fence (at least 8 feet high) around the entire garden is ideal. For a more targeted solution, individual peony plants can be protected in early spring with wire or mesh cages until they are more established and less palatable. The use of scent-based deterrents, such as commercial repellent sprays containing putrescent egg solids or garlic, can also be effective. These must be applied regularly, especially after rain, and rotated to prevent deer from becoming accustomed to them.
Strategically planting peonies among other highly deer-resistant perennials can create a garden-wide defensive barrier. Deer rely heavily on their sense of smell, so surrounding peonies with strongly aromatic plants can help mask their presence. Excellent companion plants known for their deer resistance include lavender, catmint, Russian sage, salvia, and bearded iris. The texture of these plants often complements the bold foliage and blooms of peonies while collectively creating a less inviting environment for browsing deer, further protecting your investment.
