From a botanical perspective, Delphiniums are not considered a reliably deer-resistant plant. They are not toxic enough or physically formidable enough to be a consistent deterrent. While they contain diterpenoid alkaloids, which can be mildly toxic if ingested in large quantities, deer often sample them, especially young, tender shoots and flower buds. In the hierarchy of a deer's foraging preferences, Delphiniums are not a first-choice delicacy like hostas or daylilies, but they are certainly not immune to browsing, particularly in areas with high deer pressure or during periods of scarce natural food sources.
Delphiniums possess a few inherent traits that offer a degree of protection. Their primary chemical defense is the presence of these alkaloids, which can cause discomfort or digestive upset in animals. However, deer have been known to develop a tolerance or simply ignore the bitter taste when other food is limited. Physically, the mature plant has a somewhat tough, fibrous stem, but this is not a significant barrier. The new growth in spring is exceptionally soft and succulent, making it an attractive target. The plant's strategy is not perfect defense but rather a combination of mild toxicity and rapid growth to recover from minor browsing, though severe or repeated damage can be fatal to the plant.
The likelihood of deer consuming your Delphiniums is not absolute and can vary significantly across different regions of the US. Local deer populations have distinct learned behaviors and food preferences based on their environment. In a suburban garden surrounded by lush, preferred landscaping, Delphiniums might be left alone. Conversely, in a rural area where native forage is scarce, especially in late winter or early spring, deer are far more likely to eat plants they would otherwise avoid. The local deer density is also a critical factor; higher populations lead to increased competition for food, pushing deer to expand their dietary choices to include marginal plants like Delphiniums.
To protect Delphiniums, one can employ companion planting strategies that leverage the defensive traits of other species. Surrounding Delphiniums with plants that have strong aromatic foliage or textures deer find unpleasant can create a protective barrier. Excellent deer-resistant companions include:
- **Lavender (Lavandula):** Its strong scent is a powerful deer deterrent.
- **Russian Sage (Perovskia atriplicifolia):** Features fuzzy, aromatic leaves.
- **Catmint (Nepeta):** Has a pungent smell that masks the scent of more palatable plants.
- **Yarrow (Achillea):** Its fern-like, fragrant foliage is rarely browsed.
- **Ornamental Grasses:** Their sharp-edged leaves are physically unappealing.
This approach uses a plant's natural defenses to safeguard more vulnerable specimens, creating a garden ecosystem that is less inviting to foraging deer.
