The genus Artemisia, which includes plants like Wormwood, Mugwort, and Sagebrush, is highly valued by gardeners seeking to minimize browsing damage from local wildlife. Horticulturalists widely consider Artemisia species to be deer-resistant plants. This natural defense mechanism results from unique chemical and physical properties that make the foliage unappetizing to deer.
Why Artemisia Deters Deer
The primary reason deer avoid Artemisia is the presence of potent aromatic oils and secondary metabolites within the foliage. These oils are a complex mix of volatile organic compounds, chiefly terpenes, which are released when the plant is brushed or chewed. Specific compounds like thujone, 1,8-cineole, and camphor create a strong, pungent scent that is highly repulsive to a deer’s sensitive nose.
Beyond the odor, the plant’s taste is intensely bitter due to the presence of these same chemical compounds. Deer rely on scent and taste to select their forage, and the sharp, unpalatable flavor acts as an immediate deterrent. This combination of strong scent and bitter taste signals that the plant is not a desirable food source.
The physical structure of the foliage further discourages grazing. Many popular Artemisia varieties feature fine, lacy leaves covered in tiny, soft hairs that give the plant a distinctive silver or gray appearance. This fuzzy or felted texture is often disliked by deer, which prefer plants with smooth, succulent foliage.
Varying Resistance Among Artemisia Species
While the genus overall is resistant, the level of protection is not uniform across all species. The most highly resistant varieties are those with the most pronounced silvery color and aromatic intensity. Species like Artemisia absinthium (Wormwood) and the cultivar ‘Powis Castle’ are renowned for their high concentration of defensive oils and distinctive appearance.
Less aromatic or greener-leaved species, such as certain types of Mugwort, may be occasionally sampled, especially by younger, less experienced deer. Resistance can also fluctuate based on environmental stress and the availability of other food sources. In periods of drought or deep winter snow, a starving deer may reluctantly browse on a plant it would normally avoid.
The chemical composition of the plant’s defensive compounds can also change with its growth stage. Younger plants may not have developed the full concentration of essential oils that mature, established plants possess. Gardeners should understand that “deer resistant” means the plant is generally avoided, not that it is entirely “deer-proof” under all conditions.
Protecting Artemisia in High-Pressure Deer Habitats
In areas with extremely high deer populations, even Artemisia can become a target out of desperation. Gardeners can use the plant’s natural deterrent properties as a strategic defense for other vulnerable plants. Planting highly aromatic Artemisia varieties as a border or perimeter around a flower bed can leverage its strong scent to mask the appealing odors of less-resistant species.
New plantings, particularly small nursery stock, are the most susceptible to sampling. Temporary physical protection, such as a wire cage or mesh cover, can be used for the first few months to allow the plant to establish a robust root system and develop its full chemical defense profile. This protection ensures the young foliage is not browsed before it matures.
Ensuring the plant is healthy and not stressed also supports its defense mechanism. Artemisia thrives in well-drained soil and full sun. When grown in optimal conditions, it is better able to produce the bitter and pungent oils that deter herbivores. Allowing the plant to fully mature naturally increases the volume of repellent foliage present in the garden space.