Common foxglove (Digitalis purpurea) is a herbaceous flowering plant naturally found in forests, heaths, and mountain grasslands. Common foxglove produces clusters of purple to white tubular flowers, with numerous dark spots on the inner surface. They are very attractive and commonly cultivated for ornamental purposes.
I. Appearance and Characteristics
Digitalis purpurea, the foxglove or common foxglove, is a toxic species of flowering plant in the plantain family Plantaginaceae, native to, and also widespread throughout most of temperate Europe. It has also naturalized in parts of North America, as well as some other temperate regions.
Digitalis purpurea is an herbaceous biennial or short-lived perennial plant. The leaves are spirally arranged, simple, 10–35 cm (3.9–13.8 in) long and 5–12 cm (2–5 in) broad, and are covered with gray-white pubescent and glandular hairs, imparting a woolly texture. The foliage forms a tight rosette at ground level in the first year.
The flowering stem develops in the second year, typically 1–2 m (3.3–6.6 ft) tall, sometimes longer. The flowers are arranged in a showy, terminal, elongated cluster, and each flower is tubular and pendant. The flowers are typically purple, but some plants, especially those under cultivation, may be pink, rose, yellow, or white. The inside surface of the flower tube is heavily spotted. The flowering period is early summer, sometimes with additional flower stems developing later in the season. The plant is frequented by bees, which climb right inside the flower tube to gain the nectar within.
The fruit is a capsule which splits open at maturity to release the numerous tiny 0.1-0.2 mm seeds.
Due to the presence of the cardiac glycoside digitoxin, the leaves, flowers and seeds of this plant are all poisonous to humans and some animals and can be fatal if ingested.
Digitalis purpurea grows in acidic soils, in partial sunlight to deep shade, in a range of habitats, including open woods, woodland clearings, moorland and heath margins, sea-cliffs, rocky mountain slopes and hedge banks. It is commonly found and readily colonizes sites where the ground has been disturbed, such as recently cleared woodland, or where the vegetation has been burnt. It also colonizes areas of land that have been disturbed by clear-felling and by construction projects, being among the first wildflowers to reappear, often in large quantities. Foxgloves are eurytopic plants, as their seeds germinate when exposed to light; for this reason, they are generally absent from shaded areas, such as within woodlands.
II. How to Grow and Care
Sunlight
The amount of sunlight that common foxglove requires depends on your local climate, but typically common foxglove loves a shady area to grow in with partial light. The colder your environment, for example, in the north, the more direct sun your common foxglove will need. While a mature common foxglove can withstand more shade, it will not thrive in complete shade, and this can affect growth and color intensity of its bloom.
Temperature and Humidity
Foxgloves tend to do better in cooler temperatures and may wilt in temperatures over 90 degrees Fahrenheit. Planted seeds will germinate when temperatures reach between 70 and 80 degrees Fahrenheit.
Foxgloves are not fussy about humidity, though excessive humidity may encourage some fungal diseases. Provide good air circulation by giving them sufficient spacing.
Watering
Foxglove is susceptible to crown rot, so provide it 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 thoroughly with a drip hose. Avoid overhead watering, which can encourage fungal disease.
Soil
Common foxglove can grow in a range of soils, but the optimum soil is a well-draining acidic soil with a pH value of 4.5-8.3. It is recommended to use light and loamy soil which can be purchased from most gardening centers. To ensure common foxglove remains happy and healthy, make sure that the soil is neither too dry nor waterlogging at any point.
Fertilizing
Common foxglove is a hardy plant that does not necessarily require fertilizer as long as the soil is full of nutrients, or there is a coating of compost on the soil. While this plant can be healthy without fertilizer, many do choose to use it to encourage growth and greater blooms.
In spring and summer, use a water-soluble fertilizer once a month to maintain a nutrient-rich soil which helps the plant to grow. While fertilizer is good for the common foxglove, avoid the fertilizer coming into direct contact with the leaves or flowers as the nitrogen may burn the plant.
Planting Instructions
Although common foxglove can be planted anytime throughout the year, it is recommended to plant in early spring to allow the plant to settle in warmer weather. Common foxglove can grow up to 1.5 m tall and 61 cm wide, so make sure to plant the common foxglove with plenty of space around.
This spacing will ensure proper air circulation, which will aid the growth of your plant. As your common foxglove can grow to 1.5 m tall, a good tip is to stake the taller common foxglove to prevent strong winds knocking it down.
When planting your common foxglove, ensure that the top of the root ball is nearly leveled with the surface of the soil. Covering with a good amount of mulch can ensure that your common foxglove has access to a lot of nutrients to help it flourish. It is not recommended to plant your common foxglove in containers as they can prevent plants from accessing the nutrients that are needed to grow.
Pruning
Common foxglove is a biennial flower that will only live for two growing seasons and bloom in the second season. When it reaches the second season, you should notice the buds, also known as spikes, on this beautiful plant before it starts to bloom from the beginning of summer in pink, purple, white and red. As the flowers die, cut the spike from the stalk to encourage further blooms.
Because common foxglove easily reseeds itself, be sure to dispose of your spikes away from your compost heap, if you don’t want any more of it. This is to ensure that you don’t start to grow additional common foxglove in parts of your garden where you spread your compost. Furthermore, common foxglove is poisonous, so make sure to wear gloves while pruning them. If you have pets or small children, it is not advisable to grow this plant in your garden.
Propagation
Foxgloves are generally propagated from seeds collected from the flower heads after the blooms have faded. Foxgloves seeds mature on the stalk and are ready to harvest by mid to late summer. Make sure to do it before the seed capsules have burst and spread seed around the garden.
- In mid to late summer, look for the browned seed capsules on the central flower spike of the foxglove plant. These will be at the base of the flower blossoms.
- Wearing gloves, remove the seed capsules and shake them upside down into a paper bag or envelope. The tiny seeds should be visible. Store the seeds in a dry location until planting time.
- The foxglove plant can now be pulled and discarded, as it will not bloom again (unless you have a perennial species). Again, wear gloves when handling a foxglove plant.
- To start seeds indoors: About 8 to 10 weeks before the last frost, fill trays or small containers with a seed-starter mix, then dampen the mix.
- Thinly scattered seeds across the top of the dampened seed starter mix, and cover with a thin layer of vermiculite.
- Set the tray or pots in a sheltered area with plenty of light, at a temperature of 59 to 68 degrees Fahrenheit. Check regularly and mist the soil if it becomes dry. In 14 to 21 days, seedlings should sprout.
- Continue to grow the seedlings in a bright location, thinning them out as needed. Keep the seedlings evenly moist, but not wet.
- Plant the seedlings outdoors when all danger of frost has passed. As with any indoor seedlings, harden them off for a week or so before planting outdoors.
Overwintering
Common foxgloves can be pulled up and discarded after blooming ends in late summer, as they generally do not return again. First-year plants that have not bloomed, however, should be covered with a thick layer of dried leaves or mulch after the ground freezes in late fall or early winter to moderate soil temperatures over the winter. Make sure to remove the mulch promptly in the spring to avoid crown rot.
If you wish, you can leave a few old plants in place to allow them to self-seed in the garden. In the spring, these older plants should be pulled out and discarded, as they won’t bloom again.
Caution: Wear gloves when handling foxgloves, as it is possible to absorb small amounts of toxins through the skin.
Pests and Diseases
Common foxglove can be prone to attack from insect pests including aphids, mealy bugs, slugs, and Japanese beetles. Mild infestations are often handled by predatory insects, but serious infestations can be treated with insecticidal soaps or chemical spray pesticides.
Foxglove can also be affected by a variety of funguses, such as powdery mildew, verticillium wilt, and leaf spot. Minimize these problems by giving the plants good air circulation and making sure they are planted in well-draining soil. Treat seriously affected plants with spray fungicides.
Crown rot can be a problem, sometimes caused by white fungal spores or by dense, poorly draining soils. Seriously affected plants will need to be discarded.
III. Uses and Benefits
- Ornamental uses
Common foxglove is sometimes planted in gardens as an ornamental due to its pink, purple, and white petals. It does well in the beds and borders of city, coastal, and cottage gardens. Plants such as Sage, Plume thistle, and Lilac cranesbill make good companion plants for the common foxglove.
- Medicinal uses
Extracted from the leaves, this same cardiac glycoside digitoxin is used as a medication for heart failure. Its clinical use was pioneered by William Withering, who recognized it “reduced dropsy”, increased urine flow, and had a powerful effect on the heart. During World War II, County Herb Committees were established to collect medicinal herbs when German blockades created shortages; this included Digitalis purpurea which was used to regulate heartbeat.
IV. Harvesting and Storage
Due to its colorful bloom, some people harvest the flowers of the common foxglove. These flowers will be harvested at the beginning of summer. When you are gathering its flowers, it is advisable to wear gloves.
Common foxglove is used as an ingredient for a form of heart medication and is commercially harvested throughout the year. Unless you are a trained medical expert, do not try to harvest or administer this for medication purposes. If you accidentally ingest this plant, please seek medical help immediately.
