Chrysanthemums, commonly known as mums, signal the arrival of fall with their vibrant colors, making them a fixture in seasonal garden displays. The presence of local wildlife, particularly deer and rabbits, often raises concern over their survival. Understanding the natural defenses of the chrysanthemum and the behavior of these herbivores is key to protecting seasonal plantings.
The Resistance Status of Mums
Mums are generally classified as “moderately resistant” or “less palatable” to both deer and rabbits, rather than being completely immune to foraging. This resistance stems from a natural defense mechanism involving chemical compounds within the plant’s structure. Mums produce volatile organic compounds (VOCs) that give them a pungent, distinctive aroma, acting as a primary deterrent.
The bitter taste is caused by secondary metabolites, such as sesquiterpene lactones and pyrethrins, concentrated in the foliage. When an animal attempts to eat the plant, these compounds irritate the mucous membranes and signal unpalatability, often leading to immediate rejection after a single bite.
Factors That Influence Grazing
The resistance of chrysanthemums is not absolute, and environmental conditions can override an animal’s natural aversion. Scarcity of preferred food sources is the most significant factor, as deer and rabbits become less selective when facing hunger, such as during drought or harsh winter months. In these lean times, the energy provided by the plant outweighs the negative taste experience.
The density of the local pest population also increases browsing pressure, raising the likelihood of damage to even moderately resistant plants. Not all chrysanthemums possess the same level of chemical defense. Some modern hybrid varieties bred for ornamental qualities may have lower concentrations of the bitter compounds found in older, more traditional mum cultivars. Young, tender growth is also often more appealing than mature, fibrous foliage.
Effective Deterrent Strategies
Protecting mums from browsing animals requires a multi-faceted approach that combines physical obstacles and sensory deterrents. The most reliable method involves installing physical barriers to make the plants inaccessible. For deer, a fence must be at least six to eight feet high, as they are capable jumpers. Temporary wire or fishing line strung at multiple heights can also serve as a psychological barrier. For rabbits, a low perimeter fence or wire mesh caging approximately two feet high, secured to the soil, is usually sufficient to prevent access. Cages are especially useful for protecting individual, container-grown mums.
Repellent Application
Repellents target the animals’ sense of smell or taste and are divided into two main categories. Taste-based repellents, often containing ingredients like raw eggs, garlic, or capsaicin, are applied directly to the foliage to make it unappetizing. Scent-based products use strong odors, such as putrefied eggs or animal urine, to signal danger or territorial presence. These should be applied around the perimeter of the planting area.
It is important to rotate the type of repellent used every few weeks, as deer and rabbits can quickly become accustomed to a single deterrent. Most liquid repellents must also be reapplied after heavy rainfall to maintain effectiveness.
Habitat Management
Adjusting the immediate environment can make the garden less inviting to wildlife. Rabbits are drawn to dense cover for nesting and hiding, so removing brush piles, tall weeds, and low-hanging branches near the garden perimeter can reduce their presence. Strategically planting strong-scented companion plants nearby can help mask the mums’ scent, hiding them from foraging animals. Highly aromatic herbs are excellent choices for creating a natural barrier that deer and rabbits tend to avoid:
- Lavender
- Rosemary
- Chives
- Members of the Allium family