Agastache, commonly known as hyssop or hummingbird mint, is a versatile flowering perennial and a member of the mint family. It is widely considered a highly deer-resistant plant, making it an excellent choice for gardeners dealing with browsing animals. This resistance is a natural defense mechanism, allowing the plant to thrive in areas where other foliage is quickly consumed.
Why Agastache Detours Deer
The plant’s strong, pungent aroma is the primary reason it is consistently rejected by deer, whose feeding habits rely heavily on their sense of smell. This intense fragrance comes from concentrated volatile organic compounds found within the plant’s essential oils. The bitter, unpalatable taste is a secondary deterrent that confirms the initial sensory warning.
Scientific analysis of Agastache essential oil reveals a complex chemical composition that deer find offensive. Key compounds include estragole, which contributes the plant’s characteristic anise-like or licorice scent. Other terpenes like menthone, limonene, and beta-caryophyllene combine to create a flavor profile that is strongly medicinal or minty. These chemical defenses are highly effective, placing Agastache on lists of plants rarely damaged by browsing mammals.
Factors That Reduce Resistance
While Agastache is highly unappealing to deer, no plant is entirely deer-proof, especially under certain environmental conditions. The most significant factor that can override a deer’s natural aversion is extreme hunger or starvation, particularly during harsh winter months when preferred forage is scarce. In these desperate situations, deer may sample or consume nearly any plant available, including aromatic varieties they would normally ignore.
Regional variations in deer population behavior also play a role. Young or newly dispersed fawns are less discerning in their diet than mature adults and may test the plant simply out of curiosity. Furthermore, the resistance level can fluctuate with the plant’s maturity. Deer may be more inclined to nibble the soft, tender growth that emerges early in the spring, which often contains a lower concentration of the protective essential oils than the fully developed leaves.
Gardeners can maximize Agastache’s deterrent effect by using it strategically in the landscape. Planting Agastache near more vulnerable plants acts as a natural protective barrier, forcing browsing animals to encounter the strong scent first. Placing Agastache in high-traffic deer areas leverages the plant’s chemical defenses to protect the entire garden.