Dahlias are popular ornamental flowers, cultivated for their vibrant colors and striking forms. The question of whether deer will eat them is common among gardeners. While dahlias are often listed as deer-resistant, no ornamental is entirely safe from a hungry deer. Deer typically avoid dahlias if more palatable food is available, but they will consume the foliage and blooms when other food sources are scarce.
Understanding Deer Feeding Habits
A deer’s diet is heavily influenced by the availability of natural forage, which changes seasonally and regionally. In the spring, deer prioritize new, tender growth and shoots that offer high protein content to recover from winter and support gestation. During summer and fall, their diet shifts to include mast crops like acorns and various fruits, though they browse on diverse vegetation to meet daily intake requirements.
Environmental pressure often overrides natural preferences, determining what a deer will eat. During drought or heavy snow, when natural forage is limited, deer are forced to browse less desirable plants. High population density also increases landscape damage, as competition for food sources rises significantly. When habitat capacity is exceeded, deer will feed on almost anything to survive, including plants they typically avoid.
Assessing Dahlia Palatability
Dahlias possess natural defenses that make them a low-preference food source for browsing deer. The primary deterrent is the presence of defensive chemical compounds, such as polyphenols and tannins, within the plant tissue. These compounds cause an astringent, bitter flavor and a dry mouthfeel.
Tannins bind to proteins, which can interfere with nutrient absorption, making the plant less appealing to foraging animals. This bitter taste and potential for digestive interference often cause deer to take a single bite and move on. Additionally, mature dahlia stems become fibrous and tough, a less succulent texture that deer prefer to avoid in favor of softer foliage.
The plant is generally not toxic, but it is unpalatable enough that many deer ignore it unless desperate. Rutgers University classifies dahlias as “Occasionally Severely Damaged,” confirming they are not a preferred food but remain vulnerable under certain conditions. Young, newly established plants with tender stems and buds are often more tempting than fully mature, fibrous stalks later in the season.
Protecting Your Dahlia Blooms
Since no plant is truly deer-proof, gardeners should employ a multi-layered strategy to protect their dahlia blooms. One reliable method involves establishing a substantial physical barrier. Because deer are capable jumpers, a permanent fence should be at least seven to eight feet tall. For smaller beds or individual plants, temporary measures like wire mesh cages or lightweight netting can deter browsing by physically blocking access.
Chemical repellents work by appealing to a deer’s strong sense of smell and taste, making the plants undesirable. These repellents fall into two main categories: taste-based formulas and scent-based products. Taste-based formulas contain substances like rotten egg solids or capsaicin. Scent-based products mimic the smell of a predator or are simply foul-smelling.
Repellents must be applied directly to the foliage and require reapplication every seven to fourteen days, especially after significant rainfall, to maintain potency. To prevent deer from becoming accustomed to a single deterrent, rotate between two or three different types of repellents throughout the growing season.
Combining Deterrents
Combining a repellent with a physical barrier, such as a low-level wire fence or a motion-activated sprinkler, creates an environment deer perceive as hazardous. Strategically planting strongly scented herbs, such as lavender or rosemary, near your dahlias can also act as a companion planting deterrent. These herbs help mask the scent of the desired blooms.