Foxglove Plants

Digitalis: Tall, Toxic, and Foxy

Picture of foxglove flowers. Foxgloves are poisonous plants.
Kristine Paulus/ Flickr

Taxonomy and Botany of Foxglove Plants

Plant taxonomy classifies the most commonly grown foxglove plants as Digitalis purpurea. Also mentioned below will be some other species (plus cultivars and a hybrid type), including Digitalis grandiflora.

Most types of foxglove plants are grouped with the biennials in the field of botany. Leaves form a rosette that grows close to the ground the first year. The second (and final) year, you get a spike with blooms.

But under the right growing conditions, they often last longer, blooming another year or two beyond what their "biennial" status would warrant. In this case, they may be considered herbaceous perennials. The most reliably perennial species is said to be D. grandiflora.

Further complicating any positive life-cycle identification for the novice is the fact that foxglove plants often reseed themselves. As a result, what appears to be the same plant coming up again from last year may actually be a seedling from it.

Characteristics of This Biennial

Foxglove plants are tall, slender biennials at 2-5 feet in height and just 1-2 feet wide. Many tubular, often freckled flowers bloom on a spike. They are usually nodding flowers that range in color from purple to white. The white ones can be used in moon gardens. Bloom time is in the early summer months (late spring in warm zones). Remember that, if your plant is a biennial, it will not produce flowers in its first year (there is nothing wrong with your plant; it is simply not its nature to bloom in that first year).

Growing Zones, Place of Origin, Sun and Soil Requirements

These flowers can be grown in USDA plant hardiness zones 4-8. Apply a 3-inch layer of mulch for winter protection if your region is borderline zone 4. They are native to the Old World but will sometimes naturalize in other regions.

Grow foxglove plants in full sun, partial sun, or partial shade in a fertile, well-drained, acidic soil.

Once mature, they tolerate dry shade, but not full shade. Gear the amount of sunshine you give this biennial to where you live. If you live in the South, give it some shade. In the North, you can grow it in a range of sunlight conditions, from full sun to partial shade, although it will perform best in partial sun.

Uses in Landscaping, Care, Types, and a Warning

Because of their height, foxglove plants are good for the back row of a flower border. These tall specimens are also considered classic plants for cottage gardens. They are among the flowers that attract hummingbirds.

They can get crown rot, so provide them with good drainage. Powdery mildew disease and leaf spot are other problems that can affect foxglove plants. Try to have good air circulation by giving them sufficient spacing. Foxgloves come in different sizes, and you will want to tailor your spacing accordingly. But, on average, it is a good idea to space them about 2 feet apart. You will want to stake the taller types to prevent them from flopping over in a wind storm. Do not deadhead these biennials if you want them to reseed for you.

Cultivars, other species (that is, beyond D. purpurea), and a hybrid of note include:

  1. 'Goldcrest' (yellow blooms).
  2. D. obscura (orange flowers).
  3. 'Candy Mountain' (bright, rosy-pink flowers that face upwards rather than nodding down).
  4. D. grandiflora (yellow flowers that are larger than average).
  5. D. x mertonensis (very large, coppery-pink blossoms; a hybrid plant with D. purpurea and D. grandiflora for parents).

Foxglove plants are among the most poisonous plants commonly grown on the landscape. Do not grow them if small children will be spending time in the yard.

Name Origin, Medicinal Use

According to the University of Arkansas Cooperative Extension (UACE), the common name derives from the old English "foxes glofa" and stems from ancient lore claiming "that foxes must have used the flowers to magically sheath their paws as they stealthily made their nocturnal raids into the poultry yards of rural folk."

Further explaining the connection, UACE notes that the flowers naturally grew on the wooded hillsides where the animals made their dens. This flower has inspired other cute common names over the centuries, including "witches' gloves" and "fairy caps."

The scientific genus name also refers to the fact that foxglove flowers are just about the right size for you to slip your fingers into them, as the Latin, Digitalis literally translates as "measuring a finger's breadth." It is easy to remember this name origin, since we sometimes refer to our fingers as "digits."

As with many poisonous plants, foxglove has been used by expert herbalists for medicinal purposes. Even today, drugs made from Digitalis are used to strengthen the heart and regulate heartbeat.