Candytuft, a member of the Iberis genus, is a popular low-growing perennial often used as ground cover in gardens. It produces a dense blanket of small, white flowers in the spring, which nearly covers its dark green foliage. Gardeners frequently choose this plant for rock gardens, borders, and cascading over walls. Candytuft is generally regarded as having a high degree of resistance to deer browsing.
Candytuft’s High Resistance Rating
The consensus among agricultural extension services and experienced gardeners places Candytuft on the list of plants rarely damaged by deer. This classification reflects the plant’s low palatability, meaning deer usually avoid it if other food sources are available. Deer resistance is not a guarantee that a plant will never be eaten, but rather an indication that it is consistently among the least preferred forage options.
A resistant plant like Candytuft may be tasted or nibbled by deer out of curiosity, but it is rarely consumed to the point of causing significant damage. The reliability of this resistance makes Iberis a common recommendation for landscapes that experience regular deer traffic. This avoidance behavior stems from specific inherent characteristics of the plant that act as natural deterrents.
Biological Reasons Deer Avoid Candytuft
Candytuft’s defense against herbivores is rooted in its membership in the Brassicaceae family, also known as the mustard family. This plant group is chemically defined by the presence of glucosinolates, which are sulfur-containing compounds. When the plant tissue is damaged, enzymes activate these compounds, breaking them down into sharp, bitter-tasting substances like mustard oils.
The strong, unpalatable flavor and smell created by these chemical reactions act as a potent deterrent to deer. The species name Iberis amara even reflects this defense, as amara is Latin for “bitter.” The foliage itself is dark green and leathery, making it physically less appealing to browse compared to soft, tender leaves. This combination of bitter chemistry and tough texture makes the plant an undesirable food source.
Environmental Factors That Override Resistance
No plant is entirely deer-proof, and environmental conditions can temporarily override Candytuft’s natural resistance. Deer are more likely to consume less palatable plants when their preferred forage is scarce due to external pressures. Prolonged periods of drought or a harsh winter can severely limit a deer’s food supply, leading them to browse on nearly any available vegetation.
High deer population density in an area can also increase feeding pressure, forcing animals to explore less desirable options like Candytuft. Young plants or tender new growth, particularly in the spring, may contain lower concentrations of the bitter glucosinolates, making them temporarily more vulnerable to browsing.