Deer are common visitors to many gardens, and their browsing habits often create anxiety for gardeners protecting perennial crops. Asparagus, a prized vegetable, is frequently a target of various wildlife, leading many to wonder if deer pose a threat to their harvest. The vulnerability of the asparagus plant changes throughout its growing season, from delicate spring shoots to mature, fern-like foliage. Understanding deer feeding preferences and damage patterns is the first step in successfully protecting this long-term investment.
Deer Palatability and Preference
Deer are opportunistic foragers whose diet shifts based on seasonal availability and nutritional needs, making asparagus a moderately palatable target. The young, tender spears that emerge in early spring are highly attractive because they are succulent and packed with nutrients. High in water content and amino acids like asparagine, these shoots offer a quick source of energy and protein when other food sources are scarce after winter.
Palatability changes dramatically once the asparagus spears mature and “fern out” into tall, woody stalks. These mature ferns develop a tougher texture and contain compounds that make them less appealing to deer. While deer usually avoid this woody growth, the plants are not entirely deer-proof. If natural food is scarce or deer density is high, the animals will consume less-preferred plants, including the mature ferns.
Identifying Deer Damage to Asparagus
Accurately identifying the source of damage is important for selecting the correct protection method. Deer browsing on asparagus is characterized by a ragged, torn appearance on the stalk or stem. This distinct look is caused by the deer’s lack of upper incisor teeth, forcing them to rip the plant material rather than making a clean bite. Damage typically occurs between one and six feet off the ground, targeting the growing tips of the tall ferns or emerging spears.
In contrast, damage from smaller ground pests like rabbits or groundhogs appears as a clean, angled cut, resembling a precise clip. Rabbits feed close to the soil line, often just inches above the ground, making their damage easy to distinguish from the higher browsing of deer. Noticing the height and the specific nature of the cut determines if a deer is the culprit.
Effective Protection Methods
The only reliable way to prevent deer damage is through the installation of a physical barrier. A woven-wire fence must be at least eight feet high to effectively exclude deer, as they are capable jumpers. Fences seven feet high or less may act as a deterrent but do not guarantee complete protection. For the short harvest season, a more economical approach is using temporary netting or caging around the asparagus bed, which is removed once the spears grow into ferns.
Deterrents offer a secondary line of defense by making the plants taste or smell unpleasant. Contact repellents, such as those made from egg solids, are applied directly to the plant to create a foul taste. Area repellents, including strong-smelling granules or liquids, are spread around the perimeter to repel deer by odor. Both types require frequent reapplication, especially after rain, and should be rotated periodically to prevent deer from becoming accustomed to a single product.