Deer presence presents a common challenge for gardeners. When assessing plant safety, understand that “deer resistance” is relative, not absolute. Deer are opportunistic feeders whose diet shifts based on local factors like population density and available food sources. A plant ignored in one region may be heavily browsed in another where food is scarce. Success depends on understanding a plant’s general palatability and employing protective measures tailored to the specific environment.
Deer Preference for Zinnias
Zinnias are generally considered a moderately preferred option. The mature foliage possesses a coarse, bristly texture that is less appealing to deer than smoother leaves. This rough surface, combined with a slightly aromatic nature, serves as a mild deterrent for grazing animals.
Browsing damage often concentrates on the new, softer growth at the stem tips, especially when the plant is establishing itself early in the season. Once the plant has fully matured and its stems have hardened, deer are more likely to sample a leaf or two and move on. Both large and compact varieties share this moderate resistance due to similar leaf characteristics.
Deer Preference for Cosmos
Cosmos flowers are often listed as highly resistant to deer browsing. This resistance is attributed to textural and bio-chemical factors that make the plant unappetizing. The leaves and stems contain a slightly bitter taste and often emit a distinct, strong scent that deer typically avoid.
The delicate, fern-like foliage is not the dense, high-calorie forage deer favor. While mature plants are generally avoided, a newly planted seedling or fresh flower bud remains vulnerable. This is especially true during periods of extreme food scarcity when deer are less selective about their food. The strong aversion deer have to the mature plant structure makes Cosmos significantly less likely to be damaged than Zinnias.
Practical Methods for Deer Deterrence
Gardeners can employ a layered strategy to protect both Zinnias and Cosmos from potential damage. Planting vulnerable areas close to the house or in high-traffic zones provides a psychological deterrent, as deer prefer to feed in quiet locations. For targeted protection, physical barriers are the most reliable method. These range from temporary netting placed over young seedlings to low wire cages surrounding individual plants.
Chemical repellents offer another line of defense, working through either taste or odor aversion. Taste-based products must be applied directly to the foliage and reapplied after rain or new growth emerges. Odor-based deterrents, such as strongly scented soap or commercial sprays, rely on masking the plant’s natural scent. To prevent deer from becoming accustomed to a single method, it is important to rotate between different repellent products every few weeks.