Cosmos are popular annual flowering plants known for their bright, daisy-like blooms and feathery foliage. Gardeners frequently seek them out, hoping they are a naturally rabbit-resistant choice. While mature Cosmos are often left alone by rabbits, they are not truly resistant, especially during vulnerable early growth stages. The plant’s palatability changes significantly as it develops, meaning they can be a food source under certain conditions.
The Palatability of Cosmos: A Conditional Resistance
The resistance of Cosmos to rabbit browsing is conditional, tied directly to the plant’s maturity and texture. Young Cosmos seedlings are highly vulnerable because their stems and foliage are tender and succulent, lacking the tougher structure of older growth. This soft, easily digestible tissue makes them an appealing snack for a grazing rabbit. As the plant matures, its resistance increases due to a change in physical and chemical properties. The stems and leaves become more fibrous and tougher to chew, which is less appealing. Mature foliage may also develop a slightly bitter or pungent taste from secondary compounds.
Factors Influencing Rabbit Feeding Choices
A rabbit’s decision to eat a less-preferred plant like a mature Cosmos is driven by external pressures rather than taste preference alone. Extreme hunger, particularly during early spring when other food sources are scarce, can override a rabbit’s natural aversion. When primary food sources like clover, dandelions, and tender grasses are unavailable, rabbits will expand their diet. Local rabbit population density also increases competition for preferred forage. In densely populated areas, less palatable plants are consumed because tastier options have been exhausted. Furthermore, environmental conditions, such as drought, can limit the availability of succulent wild plants, forcing rabbits to graze on garden plantings.
Effective Strategies for Protecting Young Plants
Protecting Cosmos is most important during the first four to six weeks of growth when they are at their most vulnerable stage. The most reliable method of exclusion is the use of physical barriers around the planting area.
Physical Barriers
A fence constructed from chicken wire or hardware cloth with a small mesh size, ideally one inch or less, is highly effective. To prevent rabbits from burrowing underneath, the barrier should be at least 18 inches high and secured into the ground to a depth of six inches, bent outward in an “L” shape. For individual plants or small groupings, creating small, temporary cages from the same wire material can protect the tender seedlings.
Chemical Deterrents
Topical deterrents can also be applied to the foliage, acting as a secondary line of defense. Commercial repellents often contain ingredients like dried blood, garlic, or putrescent egg solids that deter rabbits with a strong scent or taste. Homemade sprays incorporating cayenne pepper or garlic powder are also used to create an unpleasant flavor on the leaves. These repellents must be reapplied frequently, especially after heavy watering or rain, or as new, unprotected foliage emerges.
Other Flowers Rabbits Typically Leave Alone
Gardeners seeking flowers with a higher level of natural resistance have alternatives that rabbits generally avoid due to inherent properties.
- Plants with a strong, pungent aroma, such as lavender, Russian sage, or ornamental allium, are rarely targeted.
- The presence of chemical compounds that are mildly toxic or unpalatable, such as those found in foxglove or snapdragons, acts as a deterrent.
- Other species are avoided due to their tough, fuzzy, or prickly texture, including bee balm and iris.