The common foxglove (Digitalis purpurea) is a striking plant frequently encountered in gardens and wild landscapes across various temperate regions. This species is easily recognized by its dramatic vertical presence and distinctive flowers. Identifying this plant involves recognizing its unique structure, from its flowering stalk to the texture of its leaves.
The Towering Flower Spike
The most prominent feature of the foxglove is its towering, upright flower stalk, which can reach heights of up to six feet in mature plants. This main stem supports a dense, elongated cluster of blossoms known as a terminal raceme, often with the individual flowers nodding to one side. The overall effect is a dramatic, vertical spire that draws the eye upward.
The individual flowers possess a unique, tubular or bell-like form, resembling a thimble, which gives the plant its common name. While the species is most famous for its vibrant purple or magenta blooms, variations can produce pink, white, and even yellow flowers. The interior of the blossom is patterned with dark spots, which act as nectar guides for pollinators, particularly bumblebees. The flowers open progressively from the bottom of the stalk upward, ensuring a prolonged blooming period throughout the early to mid-summer months.
Identifying Leaves and Growth Habit
Foxglove typically follows a biennial life cycle, completing its life over two growing seasons. During the first year, the plant remains low to the ground, forming a dense cluster of leaves known as a basal rosette. The leaves are large, often growing up to 12 inches in length, with an ovate or lance-like shape.
The leaf texture is notably soft and downy, covered in fine, gray-white hairs, particularly on the underside, which also features prominent veins. The edges of the foliage are typically serrated, or finely toothed. In the second year, the central flower spike emerges from this overwintered rosette, with smaller, alternate leaves located directly on the flowering stem. This plant is commonly found in semi-shady locations, such as woodland edges, clearings, and disturbed ground, flourishing in rich, moist soil.
A Critical Note on Toxicity
Despite its beauty, Digitalis purpurea is a highly poisonous plant, and all parts pose a significant health risk if ingested. The plant contains a potent class of compounds called cardiac glycosides, including digitoxin and digoxin. These substances directly affect the heart muscle and can cause severe symptoms, including irregular heart rhythms, nausea, vomiting, and even death.
Accidental ingestion can occur when the leaves are mistaken for edible herbs, such as comfrey, especially when the foxglove is only a first-year rosette without a flower spike. While these compounds are used pharmaceutically to treat heart conditions, the concentration in the raw plant is uncontrolled. Therefore, great care must be taken around foxglove, and it should never be consumed.