Sweet Alyssum (Lobularia maritima) is a low-growing annual known for forming a fragrant, delicate carpet of tiny flowers. Gardeners frequently use this plant as a ground cover or border due to its prolific blooming and sweet, honey-like scent. Alyssum is generally regarded as deer-resistant. However, this resistance is not a guarantee of immunity, and certain environmental conditions can lead to browsing.
The General Consensus on Alyssum Resistance
Alyssum’s classification as a plant deer avoid is due to its inherent physical and chemical properties. As a member of the mustard family (Brassicaceae), its leaves contain acids that contribute to a pungent, peppery flavor. Deer have highly sensitive palates and often reject the plant after a single exploratory nibble of this unpalatable taste.
The strong, unpleasant flavor acts as the plant’s natural defense mechanism against herbivores. The plant’s strong fragrance, while pleasing to humans, also serves as a deterrent to browsing animals. This combination of scent and bitter taste makes Alyssum a poor choice when more palatable forage is available.
The plant’s low-growing, dense habit means it offers little substantial nutrition compared to other garden plants. For this reason, Alyssum is frequently listed by horticultural experts as being “Rarely Damaged” by deer. This designation indicates that even in areas with high deer traffic, the plant is typically among the last to be consumed.
Environmental and Behavioral Factors That Override Resistance
No plant is completely deer-proof, and resistance is relative to the deer’s motivation. The most common factor overriding aversion is severe food scarcity, such as during drought or harsh winter when preferred food sources are unavailable. During these periods, deer will consume plants they would normally ignore in order to survive.
The density of the local deer population also influences browsing pressure on resistant plants. In areas with high population numbers, competition forces deer to expand their diet, leading them to test less desirable garden plants. A large herd is more likely to cause damage than a single occasional visitor.
The behavior of younger animals can also contribute to unexpected browsing damage. Juvenile deer, or fawns, are inexperienced foragers still learning which plants are safe and palatable. These naive animals may be more experimental and try plants like Alyssum that adult deer have learned to avoid.
Active Methods for Protecting Alyssum
If Alyssum is being browsed in a high-pressure area, gardeners can employ several active strategies to enhance its natural resistance. Strategic planting is a low-effort technique that involves positioning Alyssum near other plants deer consistently dislike due to their intense aroma. Planting it alongside highly scented herbs like lavender, sage, or mint creates a sensory barrier that strengthens the deer’s aversion.
Physical barriers offer the most reliable form of protection, though they require more effort. For total exclusion of an entire garden area, a fence height of at least seven to eight feet is the standard, as deer are capable of clearing lower obstacles. For small, temporary enclosures, a five to six-foot tall fence can be adequate if the deer cannot see a clear landing spot on the other side.
Repellents work by targeting the deer’s strong sense of smell and taste. DIY spray mixtures that use the sulfurous odor of rotten eggs are particularly effective, as the scent is repulsive to deer. A common recipe involves mixing raw eggs, water, and liquid dish soap, which acts as an adherent to help the mixture stick to the foliage. This repellent must be reapplied every two weeks or immediately after significant rainfall to maintain its efficacy.