Foxglove (Digitalis purpurea) is a medicinally important, highly toxic and attractive herbaceous flowering plant. Although native to Western Europe, foxglove has naturalised in the United States and Canada. It works well in woodland gardens, according to the Missouri Botanical Garden, and makes a showy addition to borders, flower beds and naturalised areas.
Foxglove plants grow between 2 and 5 feet tall with a 1- to 3-foot spread depending on the cultivar. They have 5- to 10-inch long leaves that form a basal rosette, which is a circular group of leaves that grows from the ground. The plant produces a rosette the first year, but it sends up a flower spike and small stem leaves the second year. The individual flowers are bell-shaped and are approximately 2 inches long. The blossoms grow in an elongated cluster along one side of the flower spike and often droop toward the ground depending on the cultivar. They vary in colour from deep purple to creamy white, yellow or pink.
Hybrids and Cultivars
Foxglove is available in a wide variety of subspecies and varieties. Pam's Choice, for example, produces white blossoms with deep red spots on the inside, while Sutton's Apricot produces apricot-coloured blossoms. Alba yields solid white flowers while Strawberry Foxglove has pinkish-copper flowers. Glittering Prizes and Excelsior hybrids produce flowers in an array of colours, while Giant Shirley plants reach heights up to 5 feet and yield a variety of mottled pink blooms. Other cultivars include Gigantea, which produces 4- to 5-foot flower spikes and brownish-yellow blossoms, and Temple Bells, which has yellow flowers.
Foxglove plants grow best in U.S. Department of Agriculture hardiness zones 3 through 9. They propagate by seeds that germinate about two to three weeks after planting and will self-sow if environmental conditions permit. They prefer partial shade and nutrient-rich, organic, well-drained moist soil. Foxglove plants benefit from a layer of mulch and regular watering. Most foxglove plants bloom between June and September. You can encourage additional blooms by cutting off the flower stalks as soon as they flower.
Pests, Diseases and Problems
Insects such as mealybugs, mites and aphids drain sap from foxglove foliage, causing discolouration and occasional leaf loss. Foxgloves are also susceptible to diseases such as verticillium wilt, anthracnose and leaf spot. Foxglove plants are highly toxic and can be fatal if eaten. They contain chemicals called cardiac or steroid glycosides, and the pharmaceutical industry uses their leaves to create a heart medication called digitoxin or digoxin. If ingested, however, foxglove causes upset stomach, trembling, seizures, hallucinations and an irregular heartbeat or pulse, possibly followed by death.