The Asparagus densiflorus, commonly known as the Asparagus Fern, is a popular ornamental plant. Despite its common name and feathery appearance, this plant is not a true fern but a member of the Asparagaceae family, related to edible asparagus. The expansion of residential areas into natural habitats has made deer browsing a significant concern for gardeners. Assessing the plant’s inherent qualities helps determine its suitability for deer-prone areas.
Asparagus Fern’s Deer Resistance Rating
Asparagus Fern is consistently categorized by horticultural experts and agricultural extension offices as highly deer-resistant. Its inclusion in lists of plants that deer “rarely damage” provides gardeners with a strong indication of its suitability. This designation means the plant is not a preferred food source for white-tailed deer or mule deer under normal circumstances. Deer tend to avoid it, seeking plants with high nutritional value, succulent leaves, and palatable stems. The plant’s texture and taste profile make it an unappealing option compared to other ornamentals.
Plant Characteristics That Deter Browsing
The plant’s resistance stems from a combination of physical and chemical defenses evolved to discourage herbivores. Physically, the Asparagus Fern possesses sharp, needle-like structures called cladophylls, which are modified stems that act as leaves. These structures and the woody nature of the stems make the plant unpleasant to chew and difficult to consume in large quantities. Some varieties, like the ‘Sprengeri’ group, also feature small, sharp spines along the main stem, serving as an additional tactile deterrent.
Chemically, the plant contains compounds that are unappetizing or mildly toxic to grazing animals. All parts of the Asparagus Fern contain saponins, bitter-tasting compounds that can cause gastrointestinal distress. While the foliage is not highly toxic, the red berries that form after the small white flowers are considered mildly poisonous. The unpleasant taste and potential for digestive upset are factors in why deer select other food sources.
Situations That Can Override Resistance
The term “deer-resistant” is not synonymous with “deer-proof.” No plant is entirely immune to browsing, especially when external pressures are high. The most common situation that overrides a plant’s natural resistance is extreme hunger or thirst in the deer population. During periods of severe drought or harsh winter conditions, preferred food sources become scarce, forcing deer to consume plants they would normally avoid.
High deer population density, often referred to as high deer pressure, also increases the likelihood of damage to resistant plants. Where competition for food is intense, deer will sample and consume a wider variety of plants. Young deer may browse resistant plants out of curiosity before learning which species are unpalatable. Minor nibbling on the Asparagus Fern is typically a sign of these environmental pressures.
Incorporating Asparagus Fern into Deer-Resistant Gardens
Asparagus Fern can be strategically utilized in the landscape to enhance the overall deer resistance of a garden space. Its low palatability makes it an excellent choice for planting along property borders or near areas where deer frequently enter the yard. Using it as a dense ground cover can create a natural, unattractive barrier that discourages deer from venturing further into a garden bed.
The plant’s suitability for container gardening offers another practical strategy for deer-prone areas. Containers can be placed on patios or decks, which are generally less accessible to browsing deer. The Asparagus Fern can also be planted near more vulnerable, desirable plants to act as a protective screen or foreground planting. This strategic placement can make the more palatable plants less visible and accessible to passing deer.