Cosmos flowers, known for their delicate, daisy-like appearance and vibrant colors, are popular choices for gardeners seeking beauty and resilience. These annual or perennial flowering plants, belonging to the Asteraceae family, are generally easy to grow and maintain. A common concern for gardeners in areas with wildlife is whether these flowers will survive browsing pressure. This article addresses the likelihood of deer eating cosmos and provides strategies to protect them.
Deer Preference for Cosmos Flowers
Cosmos are widely classified as a low-preference food source for deer, often listed as “deer resistant” or “rarely damaged.” This avoidance stems from unappealing characteristics inherent to the plant’s structure and chemistry. The foliage has a slightly bitter taste that deer typically find undesirable, unlike the sweet leaves of many other garden plants. The texture of the leaves and stems also acts as a deterrent, as deer prefer plants that are easy to chew and digest.
Additionally, the plants contain compounds that contribute to their unpalatability, further discouraging feeding. Although no plant is completely deer-proof, the combination of strong scent, bitter taste, and fibrous texture makes cosmos a practical choice for minimizing browsing damage.
Situational Factors Driving Deer Consumption
While cosmos are generally avoided, no plant is entirely safe if a deer is motivated by hunger. Deer behavior is highly dependent on environmental pressures, which can override natural food preferences. During periods of food scarcity, such as drought, deep snow cover, or habitat loss leading to overpopulation, deer will broaden their diet to include less palatable plants.
Newly planted cosmos or tender young growth is often more appealing than mature, established plants. Young seedlings have a higher moisture content and have not yet fully developed the defensive compounds that give the mature foliage its bitter taste.
Furthermore, localized preferences exist where deer in a specific area may have adapted to eating plants typically ignored elsewhere. This often occurs due to a lack of preferred forage alternatives in their immediate environment.
Practical Strategies for Deterrence
Protecting cosmos requires a layered approach, combining physical obstacles and sensory deterrents. The most effective long-term solution is a physical barrier, such as an eight-foot-tall fence, as a calm deer will generally not attempt to jump an enclosure of that height. For smaller areas or temporary protection, physical barriers like netting or wire cages placed over vulnerable young plants can prevent browsing until the plants mature.
The strategic placement of companion plants can also help, as deer are often deterred by strongly aromatic foliage. Planting cosmos alongside herbs like lavender, rosemary, or sage, which possess strong scents and unappetizing textures, can make the entire area less appealing to grazing deer.
Chemical and scent-based repellents offer a practical, non-permanent solution for deterring deer. These repellents typically work by combining a smell that mimics a predator or a taste highly unpleasant, often containing ingredients like putrefied eggs or capsaicin.
The effectiveness of these sprays depends on frequent reapplication, particularly after rain. Rotation between different product types is required to prevent deer from becoming habituated to a single scent. Homemade solutions, such as sprays using rotten eggs and water, or hanging bars of strongly scented soap, can also serve as temporary deterrents.
Distinguishing Deer Damage From Other Pests
Accurately identifying the source of garden damage is important before implementing deterrence measures. Deer browsing leaves unique signs because they lack upper incisors, meaning they cannot make clean cuts. When deer feed, they tear or jerk the plant material, resulting in ragged, rough edges on stems and leaves.
Deer damage typically occurs at a higher level, often between one and six feet above the ground, targeting new shoots and buds. Other signs of deer presence include large hoof prints and oblong droppings. In contrast, smaller pests like rabbits and groundhogs leave damage close to the ground, usually within inches of the soil. Rabbits use sharp incisors to make clean, angled cuts on stems, creating a neatly clipped appearance that is different from the torn foliage left by deer.