Foxgloves (digitalis) are tall flowers that make excellent backdrop plantings. About 20 species of digitalis make up the genus; some are biennials and some are perennials. The name digitalis means "finger-like," so named because the individual flowers can be slipped over a fingertip. The common name probably comes from "folks' gloves," referring to fairies, the "good folk." Foxgloves are poisonous and are also called witches' gloves or dead man's bells.
Foxgloves are used for vertical interest in landscaping and are popular for cottage garden settings. They grow about 12 to 18 inches wide and about 5 feet tall. Grow foxgloves from seed or from root divisions made in the spring. Seed should be started indoors about 10 weeks before the last expected frost date. Seed is light sensitive and must not be covered, but gently pressed into the starting soil surface.
The spotted, bell-shaped flowers may be white, yellow, pink, rose, red, lavender or purple, and they grow clustered along the tall stem spikes. Hummingbirds and butterflies are attracted to the nectar-filled flowers.
Foxgloves tolerate partial shade in cool climates and prefer shade in the southern heat. They provide bright color to shade gardens and some height, which can be difficult to find in typical shade plant selections. The plant begins as a rosette of pretty gray-green leaves which are rather low growing, and then it sends up the tall flower stalk. Each stalk will bloom for about two weeks. Keep spent flower stalks trimmed and foxgloves will continue to send up new stalks all summer. To naturalize a bed of foxgloves, allow some of the last stalks to go to seed. Foxglove will reseed itself.
Overcrowding may cause leaf spot or fungal diseases. Foxgloves need humus-rich soil that is well drained to prevent crown rot.
The foxglove aphid is an insect pest that causes damage to many field-grown and greenhouse crops. The aphid's eggs breed continuously in a greenhouse, but they overwinter on foxglove plants outdoors. These aphids can carry over 30 plant viruses.
The larvae of several species of moths and butterflies eat foxglove flowers or leaves. Bacillus thuringiensis is used for organic pest control.
Foxglove contains cardiac glycosides and is the source of the heart medications Digitalin or Digoxin, used to treat congestive heart failure and cardiac arrhythmia. The therapeutic value of digitalis was written about as early as 1785 by English physician and chemist William Withering, who is credited with its discovery. Withering analyzed and identified the useful compounds in the plant.
Foxglove is toxic to humans and animals, including cats, dogs and horses. All parts of the plant are poisonous. The smaller leaves that grow on the upper part of the flower stalk are the most potent, and even a small morsel is enough to cause death.