Summersweet (Clethra alnifolia) is a deciduous shrub prized by gardeners for its late summer bloom and sweet, spicy fragrance. For many gardeners, the primary concern when selecting new landscape plants is how they will fare against local white-tailed deer populations. Establishing the typical resistance level of this shrub is a priority for those looking to maintain a beautiful, intact garden.
Summersweet’s Resistance Rating
Summersweet is widely regarded as a highly resistant plant, a significant benefit for landscapes facing regular deer presence. Horticultural authorities, such as Rutgers University, often place Clethra alnifolia in the “Seldom Severely Damaged” category on their deer resistance ratings. This classification means that deer generally avoid the plant and severe browsing is uncommon.
This resistance makes it a popular choice for planting near homes or alongside more vulnerable specimens that deer tend to favor. While no plant is entirely deer-proof, Summersweet’s reputation suggests that damage is infrequent and usually minor.
Factors Contributing to Deer Avoidance
The primary reasons deer avoid Summersweet are rooted in the plant’s inherent physical and chemical makeup. Deer rely heavily on their sense of smell to forage, and plants with strong, pungent scents are often unappealing to them. The shrub’s highly aromatic foliage and flowers, which give it the common name Sweet Pepperbush, act as a natural deterrent.
The scent, though pleasant to humans, is often described as spicy or slightly peppery, translating to unpalatability for grazing deer. Beyond the strong aroma, the plant’s texture also plays a role in its resistance. Deer tend to reject plants with tough, leathery, or rough leaves, making the foliage of Clethra alnifolia a less desirable texture compared to softer browse options. These combined characteristics make the shrub an unlikely primary food source, especially when alternative forage is abundant.
Managing Deer Pressure Around Summersweet
While Summersweet possesses a high degree of natural resistance, it can still experience browsing damage under extreme conditions like high deer density or severe winter food scarcity. Deer will consume almost any vegetation if they are desperate for food. Young, newly planted shrubs are often more vulnerable, as their growth is tender and less established.
Protecting new plantings can involve using temporary physical barriers, such as draping deer netting over the shrub and securing it to the ground. This physical exclusion prevents deer from accessing the tender growth until the plant matures and its inherent defenses are more robust.
Commercial deer repellents can be highly effective, typically working by creating an offensive scent or an unpleasant taste. Alternating between different brands can prevent deer from becoming accustomed to a single product. Repellents must be reapplied frequently, especially after heavy rain or during periods of rapid new growth, to maintain effectiveness. Using Summersweet as a fragrant border plant can also strategically deter deer from entering areas with more vulnerable plants deeper within the garden.