Lily of the Valley (Convallaria majalis) is a groundcover known for its delicate, bell-shaped white flowers and sweet fragrance. Gardeners often plant it in shady areas where other flowers struggle. For those in regions with high wildlife presence, a common concern is whether this perennial will be targeted by hungry deer.
Highly Resistant to Deer Browsing
Lily of the Valley is considered highly deer resistant, making it an excellent choice for gardens with significant deer traffic. Horticultural classifications categorize the plant as “rarely damaged” or “seldom eaten” by deer. This resistance suggests deer will pass over the plant for nearly any other available food source.
The plant’s strong scent and unpalatable taste deter deer from browsing. Deer rely on smell and taste to choose forage. Damage is generally only observed in extreme conditions, such as severe drought or winter starvation, when preferred food is unavailable.
The Source of the Deterrent
Deer avoid Lily of the Valley due to potent chemical compounds found throughout the plant. Convallaria majalis contains approximately 30 types of cardiac glycosides. These glycosides are present in all parts of the plant, including the leaves, flowers, berries, and underground rhizomes.
The most prominent toxin is convallatoxin, which acts similarly to the digitalis found in foxglove. When ingested, these compounds interfere with the sodium-potassium pump in the body’s cells, directly affecting the heart. This interference can cause severe digestive upset, nausea, vomiting, and lead to serious cardiac issues and irregular heartbeats.
Deer possess a highly developed sense of smell and taste that allows them to detect these bitter, toxic compounds. This natural defense mechanism protects them from ingesting substances that cause sickness or heart failure. The presence of cardiac glycosides ensures that deer recognize and reject Lily of the Valley as a food source.
Essential Safety and Growth Facts
While deer resistance is a benefit, gardeners must be aware of the plant’s toxicity to humans and household pets. The cardiac glycosides that repel deer are highly toxic if ingested by children, dogs, or cats. Consumption of any part of the plant can lead to vomiting, diarrhea, a drop in heart rate, and potentially fatal cardiac arrhythmias.
Exercise caution when planting this species near pets or young children, and always wear gloves when handling it to avoid skin irritation. Convallaria majalis also has an aggressive growth habit. It spreads rapidly through an extensive network of underground stems called rhizomes.
This spreading can quickly form dense colonies, potentially choking out other plants. Because of this tendency, Lily of the Valley is considered invasive in certain regions. It may require physical barriers or regular containment to prevent it from escaping its intended planting area.