Buckthorn, a woody shrub originally from Eurasia, is now widespread across many North American landscapes, found in woodlands, roadsides, and open fields. Its prevalence often leads to a common question: do deer eat buckthorn, and how much?
Deer and Buckthorn Consumption
Deer do not consider buckthorn a preferred food source. They may browse its leaves and twigs, but only when more palatable options are scarce. Buckthorn is not a primary part of a deer’s diet, and consumption is minimal compared to native vegetation. Deer might occasionally eat the berries, but these are not a significant part of their foraging habits.
Factors Affecting Deer’s Diet Choices
Deer avoid buckthorn due to its low palatability and specific compounds. Buckthorn contains chemicals like emodin, which can make the plant unappetizing or cause a laxative effect. This compound is found in the bark, leaves, and unripe berries. Deer instinctively prioritize more nutritious native plants when available, as these offer better nutritional value. While deer may browse buckthorn during lean times, such as late fall or winter, it remains a last resort.
Ecological Effects of Buckthorn
Buckthorn’s presence has environmental consequences because deer do not effectively control its growth. As an invasive species, buckthorn outcompetes native plants by forming dense thickets that block sunlight. It alters soil chemistry by increasing nitrogen levels, making it difficult for native species to thrive, even after removal. This invasive plant reduces biodiversity, degrades wildlife habitat, and negatively impacts forest regeneration. Buckthorn berries offer poor nutritional value to birds and can have a laxative effect, contributing to the plant’s spread as birds disperse its seeds.
Effective Buckthorn Management Strategies
Since deer do not provide effective control, direct management of buckthorn is necessary. Manual removal works for smaller plants; seedlings less than half an inch in diameter are often hand-pulled, especially when the soil is moist. For larger plants up to two inches in diameter, tools like a weed wrench provide leverage for removal.
When dealing with mature buckthorn, which can grow up to 25 feet tall, the cut-stump method is a common strategy. This involves cutting the stem close to the ground and immediately applying a herbicide to the cut surface to prevent resprouting. Herbicides containing glyphosate or triclopyr are often recommended, applied within minutes to the outer ring of the stump where the plant’s vascular tissue is located. Alternatively, covering the cut stump with a tin can or black plastic for at least two summers can prevent regrowth without chemicals. Persistence and follow-up treatments are important, as buckthorn seeds can remain viable in the soil for several years, leading to new seedlings.