Foxglove (Digitalis purpurea) is a striking biennial or short-lived perennial prized for its tall, colorful spikes and bell-shaped flowers. It adds dramatic height to garden beds, making it a popular choice for cottage-style landscapes. Gardeners often worry about whether this plant will survive browsing pressure from common garden pests, particularly deer and rabbits.
The Chemical Reason for Avoidance
Deer and rabbits avoid foxglove due to the plant’s chemical defense system. Foxglove produces cardiac glycosides, including digitoxin and digoxin. These powerful toxins are present throughout the entire plant—in the leaves, stems, flowers, and seeds—and serve as an evolutionary strategy for deterring herbivores.
When ingested, cardiac glycosides interfere with the sodium-potassium pump (Na+/K+-ATPase) in animal cells, which regulates heart function. This interference leads to symptoms like nausea, severe digestive distress, and vomiting. In large quantities, the compounds can cause cardiac arrhythmias, serving as a lasting deterrent for browsing animals. The intensely bitter taste of the leaves further signals that the plant is unpalatable and dangerous.
Confirmed Resistance Status
Foxglove is consistently classified as highly resistant to both deer and rabbits due to its inherent toxicity. Deer rarely browse on the plant; many universities rate it as “Rarely Damaged” on resistance scales. The extremely bitter taste and resulting gastrointestinal distress quickly train deer to leave the foxglove alone.
Rabbits also instinctively avoid foxglove foliage, recognizing its toxicity. While no plant is entirely “proof” against a starving animal during severe drought or winter famine, foxglove is a last-resort food source. Gardeners can plant foxglove in open areas with confidence, as its chemical defenses provide a strong, natural deterrent against these common mammalian pests. Its presence can even help divert pests away from other, more palatable plants nearby.
Important Safety Considerations for Gardeners
While foxglove resists wildlife browsing, its potent toxicity requires careful handling by gardeners. All parts of the plant contain cardiac glycosides and are poisonous to humans and domestic pets, including dogs and cats. Gardeners should exercise caution when planting or maintaining foxglove, especially where small children or curious pets might sample the foliage.
It is advisable to wear gloves when handling the plant, particularly during tasks like deadheading, dividing, or removing spent flower stalks. This minimizes the chance of skin irritation or accidental exposure to the sap. After any direct contact, a thorough washing of hands is recommended. To protect pets, consider planting foxglove in fenced areas or locations inaccessible to domestic animals.