Asters (Symphyotrichum species) are valued flowering plants that bring vibrant color to gardens, particularly in late summer and autumn. Their daisy-like blooms make them a popular choice for extending the season of floral interest. However, local deer populations often challenge the cultivation of these perennials. This interaction raises the question of whether asters can be reliably grown without becoming a regular food source for these opportunistic foragers.
Understanding Aster Palatability to Deer
Deer are opportunistic feeders, sampling a wide variety of plants, but their preferences are influenced by local conditions. Asters are typically not a preferred food source, often receiving a “B” rating on palatability scales, suggesting they are seldom severely damaged by browsing. This low preference is attributed to the slightly bitter taste or unappealing texture of the foliage in many varieties.
Consumption increases significantly when primary, more palatable food sources become scarce, such as during dry summer periods or late into the fall. Deer are more likely to browse asters when new, tender growth appears in spring, or when colorful blooms emerge in autumn. High population pressure in a localized area can also lead to deer eating almost any available plant, regardless of its resistance rating.
Certain varieties, such as the Aromatic Aster (Symphyotrichum oblongifolium), possess pungent foliage that makes them naturally less appealing to deer. New England asters (Symphyotrichum novae-angliae) are also noted as being less favored compared to other garden staples. Observing which varieties are present and the season of browsing helps diagnose the level of threat your specific plants face.
Immediate Physical Protection Methods
The most reliable way to prevent deer from eating asters involves physical barriers that entirely exclude access to the plants. For permanent protection of a garden area, perimeter fencing must meet specific height requirements due to the animal’s jumping ability. White-tailed deer can easily clear obstacles up to six feet high.
To be consistently effective, a fixed perimeter fence should stand at least eight feet tall. In areas with high deer populations or agile animals, experts recommend heights closer to ten feet to create a psychological barrier deer are unwilling to test. The fence material should be securely fastened to the ground, as deer can squeeze underneath loose barriers.
For individual plants or small groupings, temporary caging or netting provides an immediate solution. Cylinders constructed from wire mesh, such as chicken wire or hardware cloth, can be placed around the plants and secured with stakes. This method offers a visual and physical deterrent, protecting tender shoots until the plants are fully established.
Repellent and Sensory Deterrents
Repellents discourage deer through taste or smell, making treated plants unappealing without physically blocking the animals. Commercial repellents often use ingredients like rotten eggs, capsaicin (the compound that makes peppers hot), or predator urine to activate the deer’s natural aversion responses. The effectiveness of these products relies on consistent application.
Repellents must be reapplied frequently, usually every two to four weeks, to maintain a sufficient concentration of active ingredients. Reapplication is important after heavy rainfall, which washes the product away, or during rapid plant growth where new, unprotected foliage emerges. Spraying the repellent in the early evening is recommended, as deer primarily feed under the cover of darkness.
Sensory deterrents, such as motion-activated sprinklers, provide a short-term solution by startling approaching deer. These devices use sudden noise and movement to interrupt feeding patterns, capitalizing on the deer’s natural skittishness. To remain effective, it is beneficial to rotate deterrents, as deer quickly become accustomed to a single method.
Long-Term Garden Planning for Deer Prevention
Strategic garden design minimizes the likelihood of future browsing damage to asters. One effective approach involves placing asters in areas less accessible or appealing to deer, such as close to the house or within a courtyard or fenced vegetable garden. This limits the open space deer prefer for foraging.
Companion planting involves using fragrant or unpalatable plants to create a protective buffer around vulnerable asters. Plants with strong scents, rough textures, or toxicity, like lavender, yarrow, sage, and thyme, are often avoided by deer. Positioning these resistant plants along the perimeter of the garden bed can serve as a natural border deer are reluctant to cross.
Managing the surrounding landscape can also make the garden less attractive. Deer often use dense vegetation or tall grasses near a garden as bedding areas or cover when approaching. Maintaining clear sight lines and reducing overgrown areas adjacent to the asters discourages deer from lingering near the protected plants.