The Cape Plumbago, or Plumbago auriculata, is a popular, sprawling shrub known for its long season of distinctive sky-blue flowers. Gardeners appreciate this plant for its beauty and resilience, often seeking it out to add color to their landscapes. In areas with high white-tailed deer populations, a common concern is whether this attractive shrub will be browsed and damaged.
Understanding Plumbago and its Traits
Plumbago possesses several natural characteristics that discourage deer browsing, making it a generally avoided food source. The primary deterrent is chemical, stemming from the presence of a bioactive compound called plumbagin. This compound is responsible for a bitter or pungent flavor that is highly unappetizing to deer and other mammalian herbivores.
The plant’s thin, bright green leaves also contribute to its resistance. They have minute gland dots that likely add to the plant’s unappealing nature. Furthermore, the long, thin stems of this scrambling shrub do not offer the bulk that deer prefer in browse material. These combined physical and chemical properties place Plumbago high on most deer-resistance lists.
Is Plumbago Truly Deer Resistant?
Plumbago is consistently labeled as deer-resistant, meaning it is not a preferred food source and deer will typically choose other options first. This label should not be mistaken for “deer-proof,” as no plant is completely immune to browsing. The effectiveness of its natural defenses is heavily influenced by environmental conditions and local deer population dynamics.
Deer are opportunistic feeders, and their behavior changes significantly when preferred food sources become scarce. During periods of drought, deep snow cover, or overpopulation, deer pressure can become intense. This forces the animals to browse plants they would normally avoid, and the plumbagin content may not be enough to deter a hungry deer seeking nutrition.
Tender new growth on the shrub can be particularly vulnerable to browsing, as fresh shoots may contain lower concentrations of the bitter plumbagin than mature leaves. A deer might “sample” a plant, causing noticeable damage even if it does not consume the entire shrub. While Plumbago is a safe choice for a deer-prone area, homeowners must remain vigilant, especially during winter when food is naturally scarce.
Strategies for Preventing Deer Damage
Gardeners who still experience browsing on Plumbago can employ a combination of physical and sensory strategies. For young or newly established shrubs, temporary physical barriers, such as wire cages or netting, can be used until the plants mature. Permanent fencing, ideally reaching eight feet high, offers the most reliable long-term solution by preventing deer from entering the garden.
Chemical and sensory deterrents work by making the plant unappealing through taste or odor, overwhelming the deer’s sensitive sense of smell. Commercial repellents often use putrescent egg solids or blood meal, which emit a sulfurous odor deer associate with predators. Other effective taste-based repellents contain capsaicin, the compound that gives chili peppers their heat.
For a more cost-effective approach, many gardeners use homemade remedies like sprays made from rotten eggs, garlic, or hot pepper mixtures. Other sensory deterrents include hanging strongly scented soap bars, such as Irish Spring, or bags of human hair near vulnerable plants. It is necessary to rotate types and reapply them after heavy rain or approximately every two to four weeks. Planting Plumbago closer to the house or in high-traffic areas can also help, as deer are reluctant to venture into spaces with frequent human activity.