Foxgloves are eye-catching flowering plants. These are tall, slender plants with tubular blooms. Most varieties are biennials that live for only two growing seasons, but some species can survive as perennials in some climates. Foxglove plants are among the most poisonous plants commonly grown in home landscapes. Do not grow them if small children or pets will be spending time in your yard.
- Botanical name: Digitalis purpurea
- Common name: Foxglove, Witches Glove, Dead Man's Bells, Fairy Bells
- Plant type: Biennials
- Mature size: 2 to 5 feet tall, 1 to 2 feet wide
- Sun exposure: Full sun, partial sun, or partial shade
- Soil type: Well-draining, loamy soil
- Soil pH: 4.5 to 8.3
- Bloom time: Early summer months (late spring in warm zones)
- Flower color: Pink, purple, red, white, and yellow
- Hardiness zones: 4 through 10
- Native area: Europe and Northwest Africa
How to Grow Foxglove
Plant taxonomy classifies the most commonly grown foxglove plants as Digitalis purpurea. Most types of foxglove plants are grouped with the biennials in the field of botany. The first year, the plant has leaves that form a rosette close to the ground. The second (and final) year, it develops a spike with blooms. Under the right growing conditions, foxglove often lasts 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 Digitalis grandiflora.
Their blooms include multiple tubular, often freckled, flowers that form 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. 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 and they are among the flowers that attract hummingbirds.
The scientific genus name Digitalis refers to the fact that foxglove flowers are just about the right size for slipping your fingers into, as the Latin translation of digitalis is "measuring a finger's breadth." (It is easy to remember this name origin since fingers are often referred to as "digits.")
Grow foxglove plants in full sun, partial sun, or partial shade. Once mature, they tolerate dry shade but not full shade. Tailor the amount of sunshine you give this biennial to your climate. 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.
Foxglove is susceptible to crown rot, so provide them with good drainage. Keep the soil moist, but not soaked. If there is a dry period in the summer and it hasn't received 1 inch of rain in a week or the top 2 inches of soil is dry, water the plant with a drip hose.
Temperature and Humidity
Foxgloves tend to do better in cooler temperatures and may wilt in temperatures over 90 degrees Fahrenheit. They do not have any humidity requirements. The seeds will germinate when temperatures reach between 70 and 80 degrees Fahrenheit. Try to provide good air circulation by giving them sufficient spacing.
Apply a 3-inch layer of mulch for winter protection if your region is borderline zone 4. Then apply a 1-inch layer of compost around the plant in early spring to encourage growth. Fertilizer is not necessary and excess nitrogen can harm the flower growth. You can add a small handful of slow-release 5-10-5 fertilizer in the early spring. Scatter it around the plant and then water over the fertilizer to help it settle. Avoid having the fertilizer tough the foliage, as it may burn the plant.
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 the original plant.
Varieties to Grow
- Goldcrest has yellow blooms
- D. obscura has orange flowers
- Candy Mountain has bright, rosy-pink flowers that face upwards rather than nodding down
- D. grandiflora has large yellow flowers
- D. x mertonensis is a hybrid plant of D. purpurea and D. grandiflora with very large, coppery-pink blossoms
Foxgloves come in different sizes and should be spaced accordingly, but as a general rule, it is good to space them about 2 feet apart. 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.
Toxicity of Foxglove
As with many poisonous plants, foxglove is poisonous to both people and pets. The plant contains cardiac glycosides such as digitoxin, digoxin, and digitalin. The foxglove plant is actually the source of the heart medication known as digitalis. The therapeutic dose is dangerously close to the lethal dose, so administering the medication requires careful monitoring by a doctor.