Taxonomy and Botany of Foxglove Plants
Plant taxonomy classifies the most commonly grown foxglove plants as Digitalis purpurea, but I also mention some other species (plus cultivars and a hybrid type) below, including Digitalis grandiflora.
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, succeeded by a spike with blooms the second, and final year.
But under favorable 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. Numerous tubular, often flecked flowers bloom on a spike. They are usually nodding flowers that range in color from purple to white (the latter can be used in moon gardens), typically (but see below for some of the less common colors). Bloom time is in the early summer months (late spring in warm zones).
Growing Zones, Place of Origin, Sun and Soil Requirements
Once established, they tolerate dry shade, but not excessive 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 have the option of growing it in a range of sunlight conditions, from full sun to partial shade (depending on what you are looking to achieve in your landscape design), although it will probably perform best in partial sun.
Uses in Landscaping, Care, Types, and a Warning
They are susceptible to crown rot, so provide them with adequate drainage. Powdery mildew disease and leaf spot are other problems that can plague foxglove plants; promote air circulation by giving them sufficient spacing. Foxgloves do 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.
Cultivars, other species (that is, beyond D. purpurea), and a hybrid of note include:
- 'Goldcrest' (yellow blooms).
- D. obscura (orange flowers).
- 'Candy Mountain' (bright, rosy-pink flowers that face upwards rather than nodding down).
- D. grandiflora (yellow flowers that are larger than average)
- 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 whimsical 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 common names of considerable whimsy 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, "measuring a finger's breadth" (it is easy to remember this, since we sometimes refer to our fingers as "digits").
As with many poisonous plants, foxglove was traditionally used by expert herbalists for medicinal purposes. Even today, drugs made from Digitalis are used to strengthen the heart and regulate heartbeat.