The Bleeding Heart, botanically known as Lamprocapnos spectabilis (formerly Dicentra spectabilis), is a popular ornamental perennial prized for its distinctive, heart-shaped flowers that appear in the spring. Gardeners often choose this plant to brighten shaded areas, but its soft, lush foliage presents a concern for anyone gardening in a region with deer activity. This leads many to question whether this beloved plant is safe from browsing.
The Definitive Answer: Deer Resistance Rating
Bleeding Hearts are generally classified by horticultural experts as highly deer-resistant plants. This resistance rating means that deer seldom severely damage the foliage, though no plant can be guaranteed to be entirely deer-proof. They are not a preferred food source, and most deer will choose alternative forage before turning to this perennial. Their inclusion in woodland gardens is often recommended specifically because of this reliable resistance to browsing.
The plant’s resistance is based on inherent defense mechanisms rather than physical barriers or strong scents. The foliage and stems of the Bleeding Heart contain defensive compounds that make them unappealing to most browsing mammals. Deer rely on taste and smell to identify palatable food, and the internal chemistry of this plant sends a clear signal to avoid consumption.
The Source of Protection: Toxicity and Unpalatability
The primary defense mechanism of the Bleeding Heart lies in its production of specialized chemical compounds. The entire plant, including the leaves, stems, and roots, contains a variety of isoquinoline alkaloids. These compounds are mildly toxic to mammals, including deer, which acts as a deterrent against feeding.
Specific isoquinoline alkaloids identified in the Bleeding Heart include protopine, sanguinarine, and chelerythrine. When ingested, these substances can cause gastrointestinal distress, such as vomiting, diarrhea, and colic. The immediate unpleasant taste caused by the alkaloids is enough to discourage a deer from continuing to browse, effectively training the animal to avoid the plant in the future.
When Resistance Fails: Factors Leading to Consumption
Despite its chemical defenses, the Bleeding Heart is not immune to being browsed, especially under specific environmental pressures. The rating of “deer-resistant” is not the same as “deer-proof,” and extreme conditions can override a deer’s natural aversion. The most common factor leading to consumption is a lack of alternative food sources, often caused by severe weather events like prolonged drought or harsh, snow-covered winters. When preferred food is scarce, a deer’s overriding need for sustenance forces it to try less palatable options.
High deer population density in a localized area can also increase the likelihood of browsing. As competition for food intensifies, deer become less selective and may sample plants they would normally ignore. Younger deer, which are still learning which plants to avoid, might also taste the foliage out of curiosity before the bitter alkaloids deter them. This initial sampling can result in clipped stems and leaves, even if the plant is not consumed wholesale.
Protecting Bleeding Hearts from Foraging
For gardeners experiencing browsing despite the plant’s resistance, several intervention strategies provide an extra layer of protection. One effective method is the use of commercial deer repellents, which typically work either by creating an offensive odor or an unpleasant taste. Taste-based repellents, often containing ingredients like putrescent egg solids, must be applied directly to the foliage, while scent-based products work by making the area smell alarming.
Temporary physical barriers can protect plants during vulnerable periods, such as when new, tender growth first emerges in the spring. A small cage of wire mesh or lightweight netting placed over the plant can deter a curious deer until the foliage matures and its alkaloid content increases. Another strategy is companion planting, where the Bleeding Heart is surrounded by other plants that possess strong odors or textures that deer find offensive, such as aromatic herbs or plants with spiky foliage.