Asters are popular perennial plants cherished by gardeners for providing vibrant, late-season color when much of the garden begins to fade. These daisy-like flowers, largely belonging to the genus Symphyotrichum, are a welcome sight as summer ends and autumn begins. A frequent concern for homeowners is the vulnerability of these plants to common garden herbivores like deer and rabbits. Understanding the plant’s inherent defenses against these animals helps gardeners determine if asters will thrive in a landscape with active wildlife pressure.
Aster Resistance Profile
Asters show a clear distinction in how they are perceived by deer versus rabbits. Asters are generally categorized as plants that are “seldom severely damaged” by deer, often receiving a ‘B’ rating on resistance scales. Deer are selective browsers that typically avoid plants with certain physical or chemical characteristics. They find the foliage unpalatable, likely due to a slightly rough or fuzzy texture on the leaves and stems. The presence of mild chemical compounds also contributes to their low desirability compared to other vegetation.
Specific varieties, such as the Aromatic Aster (Symphyotrichum oblongifolium), possess pungent, fragrant foliage that acts as a natural deterrent. This combination of texture and taste means a deer will usually pass over asters for a more appealing meal when other food is available.
Rabbits, however, can pose a greater threat, particularly during the early growing season. These smaller herbivores browse closer to the ground and are known to nibble on new, tender spring shoots. While mature aster plants are often left alone due to tougher foliage, young plants present an easy, succulent target. Rabbit damage is usually characterized by a clean, 45-degree angle clip on the stem, which is distinct from the ragged tear left by deer.
Factors Influencing Browsing Decisions
Asters’ natural defenses do not guarantee immunity, as environmental conditions can override an animal’s typical food preferences. The most significant factor influencing browsing is food scarcity, which compels both deer and rabbits to consume plants they would normally ignore. During periods of severe drought, heavy snow cover, or late fall when preferred forage has died back, asters may become a target.
Plant Growth Stage
The growth stage of the plant also heavily influences an animal’s decision to browse. New growth emerging in the spring is softer and more palatable, making young aster plants much more vulnerable than established specimens. This tenderness lacks the tougher, fibrous stems and leaves that later deter herbivores. Furthermore, not all asters are equally resistant, as certain heavily hybridized cultivars may have had some of their natural defensive characteristics bred out.
Local Wildlife Pressure
Local pressure exerted by wildlife populations is another variable that affects browsing severity. In areas with extremely high densities of deer or rabbits, competition for food forces animals to sample a wider variety of plants, including those usually avoided. An aster left untouched in one garden may be heavily damaged in another simply because the local population is larger and more desperate for sustenance. Deer are opportunistic feeders, grazing on whatever is easiest to reach when hungry.
Practical Protection Methods
When the natural resistance of asters is insufficient, gardeners can employ several practical mitigation techniques. Physical barriers offer the most reliable form of protection and can be tailored to the specific threat.
Physical Barriers
For rabbits, low, fine-mesh fencing or temporary wire cages around young plants can prevent damage to vulnerable new growth. Protecting against deer in high-pressure areas may require more substantial perimeter fencing. This fencing should ideally reach eight feet or higher to prevent deer from jumping over.
Repellents
Repellents can also be used to make the asters less appealing, working either by taste or smell. Commercial sprays containing putrescent egg solids or capsaicin create a foul taste or odor that deters herbivores without harming the plant. These deterrents require regular reapplication, especially after rain, to maintain their effectiveness. Home remedies rely on unfamiliar or offensive smells to deter animals, such as hanging bars of strongly scented soap or scattering human hair.
Strategic Placement
Strategic placement of asters within the landscape can also reduce browsing risk. Planting asters closer to a house or patio may discourage nocturnal feeding, as animals prefer to stay in less exposed areas. Alternatively, mixing asters with highly fragrant, deterrent plants such as lavender, alliums, or yarrow can help camouflage the aster’s presence. While asters are a good choice for a resilient garden, protective measures may be necessary depending on the severity of local wildlife pressure.