Brown Eyed Susans (Rudbeckia genus) are bright, hardy flowers popular among gardeners. When deer are present, concerns arise about whether these plants can survive browsing pressure. This article addresses the relationship between deer and Rudbeckia species, detailing the plant’s natural defenses, the conditions that override them, and practical steps to keep your flowers intact.
How Deer Typically Interact with Brown Eyed Susans
Brown Eyed Susans (Rudbeckia hirta and similar species) are generally classified as deer-resistant plants, meaning deer usually avoid them. This resistance stems from physical and chemical defenses evolved to deter herbivores. The foliage and stems have a coarse, hairy texture that is unappealing to the soft mouths of browsing deer.
The plant also contains secondary metabolites, such as tannins, which give the leaves a bitter taste. Deer rely heavily on smell and taste to select food, and these compounds make the plant less palatable, discouraging repeated feeding. Resistance ratings often list Rudbeckia hirta as “Seldom Rarely Damaged,” indicating browsing occurs only when other food sources are extremely scarce. However, no plant is entirely deer-proof, especially when newly planted or under stress.
Environmental Conditions That Increase Browsing
The natural resistance of Brown Eyed Susans can be overcome by specific environmental pressures that change a deer’s feeding habits. The most significant factor is severe food scarcity, which occurs during prolonged droughts, harsh winters, or in overpopulated areas. When preferred vegetation is unavailable, deer become opportunistic feeders and will graze on plants they would normally ignore.
High local deer population density also increases browsing pressure due to competition for limited resources. Another element is the maturity of the foliage; young growth is often more tender and less bitter than the mature, hairy leaves. Deer are more likely to sample this new growth, especially in early spring when they seek high-nutritional food. These stressful conditions force deer to expand their diet, overriding their natural aversion to the plant’s texture and taste.
Effective Methods for Protecting Your Plants
Gardeners can protect their Brown Eyed Susans using a combination of physical barriers and sensory deterrents. Physical exclusion offers the most reliable protection, and fencing is the most effective method. A permanent perimeter fence should be at least eight feet high, as deer can jump considerable heights.
For smaller areas or individual plants, micro-exclosures can prevent browsing. These include wire cages, netting, or tomato cages anchored into the ground. Physical barriers should be installed before the growing season begins to prevent deer from establishing a feeding habit.
Temporary protection can be achieved through sensory deterrents that target a deer’s acute sense of smell and taste. Repellents often utilize foul-tasting or foul-smelling ingredients, such as putrid egg solids, capsaicin, or garlic. Repellents must be applied directly to the foliage and reapplied regularly, particularly after rain and on new growth. To prevent deer from becoming accustomed to a single deterrent, rotate between two or more different repellent types every few weeks.