Ornamental · Plantaginaceae
Foxglove
Digitalis purpurea
Tall spires of speckled bells brighten any shady border, yet every part of this plant is poisonous.
Partial shade
Every 3–7 days
USDA 4–9
2–5 ft · 0.6–1.5 m
Overview
Picture tall, one-sided spikes of speckled tubular bells that bees climb right into. Foxglove earns its spot at a part-shade border or woodland edge, asks for acid-loving roots and steady moisture, and ranges from the wild plant's purple all the way to white, cream, and rose in garden strains.
Most foxgloves follow a biennial path: a low leaf rosette the first year, then a flower spike that shoots up the second year, sets seed, and fades. Leave a spike or two to ripen and the plant self-seeds, so a planting carries on generation after generation.
All that beauty comes with a serious catch. Foxglove is the source of the heart drug digitalis, and every part is poisonous to people and animals, so keep it only where children, pets, and grazing animals can never reach it.
Care
The short version: give foxglove dappled part shade, keep the soil evenly moist in acidic ground, feed lightly, and space the plants so air keeps moving. Deadhead for a second flush, and treat the whole plant as dangerous to people and animals.
Light
Foxglove thrives in partial shade, the dappled light you find at a woodland edge. It will take full sun where summers stay cool and moist, and in hot regions a few hours of afternoon shade keep the spikes from wilting.
Water
Keep the soil evenly moist and water every 3 to 7 days depending on heat and rain. Letting the ground dry out brings on drought stress that cuts flower production, so a layer of mulch to hold moisture pays off.
Soil
Aim for moist, well-drained ground that runs high in organic matter. Foxglove favors acidic conditions, so target a pH of 5.0 to 6.0, work in plenty of compost, and skip the lime.
Humidity
Average humidity suits it fine, and ordinary outdoor air needs no fussing. What truly counts is airflow between plants, since still, damp air around crowded foliage invites powdery mildew.
Feeding
This is not a heavy feeder. A balanced fertilizer or compost worked into organically rich soil through the growing season, applied seasonally, keeps it satisfied.
Pruning
Snip spent flower spikes after bloom to encourage secondary bloom and curb excessive self-seeding, but leave a few standing if you want the planting to persist. Cutting flowering stalks back to basal foliage before seed sets nudges plants toward behaving as short-lived perennials.
Size & spacing
Foxglove reaches a height of 2 to 5 feet (61 to 152 cm) with a spread of 12 to 30 inches (30 to 76 cm). Set plants about 18 inches apart so air moves through and leaves stay dry.
When to plant
Foxglove runs on a patient two-year clock. Scatter seed on the surface in late spring or direct sow in late summer, move young plants out once the last frost has passed, and the tall flower spikes turn up the next May and June.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Late spring; surface-sow because seed needs light to germinate, do not cover
- Plant: Transplant or thin seedlings to about 18 inches apart after the last spring frost; can also be direct sown in late summer for bloom the following year
- Harvest: Spring to summer (May to June), with a tall one-sided flower spike in the second year
Hardiness
USDA hardiness zones: 4–9
Temperature: down to -34°C
Troubleshooting
Growing foxglove stays easy, though damp, crowded conditions open the door to a handful of fungal troubles and the usual garden insects. Spot the early clues on leaves and crown, and stepping in before anything spreads becomes simple.
Plant wilts, base of stem rots, and plant collapses
A mushy, discolored crown and roots in soggy ground point straight to crown rot, which takes hold in poorly drained or waterlogged soil. Once the crown turns soft there is no saving the plant, so remove and destroy it, fix the drainage before replanting, and steer clear of low, waterlogged spots.
Fix:
- Remove and destroy affected plants
- Improve soil drainage before replanting
- Avoid planting in low, waterlogged spots
White powdery coating or dark spots on leaves
This points to powdery mildew or a leaf spot fungal disease, both helped along by crowding and poor air circulation. A white powdery film signals mildew, while discrete brown or tan lesions mean leaf spot. Pull off and discard affected leaves, open up spacing to about 18 inches apart, and water at the base rather than wetting the foliage.
Fix:
- Remove and discard affected leaves
- Improve air circulation by proper spacing (about 18 inches apart)
- Avoid overhead watering and wetting foliage
Clusters of small insects on new growth, or chewed and skeletonized leaves
Sap-sucking aphids and mealybugs cluster on stems and leaf undersides, while Japanese beetles or slugs chew the foliage and leave slime trails and ragged holes. Blast aphids off with a strong jet of water, hand-pick the beetles and slugs, and reach for insecticidal soap when an infestation digs in. Clearing garden debris that shelters slugs keeps the pressure down.
Fix:
- Knock off aphids with a strong spray of water
- Hand-pick Japanese beetles and slugs
- Treat persistent infestations with insecticidal soap
Reduced flowering and stressed appearance
When the soil dries out, drought stress sets in and the plant turns limp through hot, dry stretches with fewer blooms to show. Water consistently to hold the soil evenly moist and mulch to lock that moisture in, since letting the ground dry out directly limits flower production.
Fix:
- Water consistently to keep soil evenly moist
- Mulch to conserve soil moisture
Toxicity
Handle this plant as genuinely dangerous. Every part carries cardiac glycosides, the very compounds behind the heart drug digitalis, and even a small amount can set off vomiting and a life-threatening heartbeat. It is severely toxic to cats, dogs, horses, rabbits, livestock, and birds, and it has poisoned people who took the leaves for an edible herb. Keep it clear of children, pets, and grazing animals, and never leave cut spikes in vase water within reach.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Severe
For cats this is severe: even a nibble is dangerous, since cardiac glycosides bring on drooling and vomiting, then a slow or wildly irregular heartbeat that can stop the heart, so treat any chewing as an emergency.
Dogs Severe
For dogs this is severe: a dog that eats any part may vomit, have diarrhea, and grow weak before its heart rhythm turns dangerous, with collapse and death able to follow, so get to a vet right away.
Horses Severe
For horses this is severe: foxglove in pasture or hay poisons them gravely, bringing colic, a staggering gait, and a heartbeat that races or stutters toward heart failure.
Rabbits Severe
For rabbits this is severe: the same heart toxins hit them hard, leaving them limp, off their food, and at real risk of sudden heart failure, so never let a rabbit reach the leaves.
Livestock Severe
For livestock this is severe: cattle, sheep, and goats are poisoned by the plant fresh or dried in hay, with drooling, gut upset, weakness, and fatal rhythm changes, and dried plants stay just as deadly.
Birds Severe
For birds this is severe: cardiac glycosides are toxic to them too, so keep poultry and pet birds well clear of every part.
People Caution
For people this is a caution and not safe to eat: no part of foxglove is food, and people have been poisoned mistaking the leaves for comfrey, since eating any of it, or even drinking water from a vase of cut spikes, can trigger vomiting and a dangerous heartbeat, so keep it well away from children.
Keep all parts of the plant away from pets, children, and livestock; wash hands after handling and do not allow any part to be eaten.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
Wild foxglove leans toward purple, but garden strains stretch the palette much wider, and several were bred to flower in their first year. These are the ones worth knowing.
Foxy
Foxy is a compact strain that tops out around 2 to 3 feet in white, cream, and rose, and it often flowers in its first year from seed.
Camelot
Camelot is a first-year-flowering cultivar that blooms the same year when sown in fall for the following spring.
Dalmatian
Dalmatian is a first-year-flowering series bred to bloom the first year from seed instead of waiting a second season.
Temple Bells
Temple Bells is a dwarf type carrying yellow tubular flowers brushed with brown markings.
How to propagate
Foxglove grows from seed, and the only real trick is that the seed needs light to sprout.
SeedEasy
Surface-sow indoors in late spring or direct sow in the garden in late summer/spring after frost danger passes · Forms a basal rosette the first year and flowers the second year; first-year-flowering cultivars can bloom about 5 months from an early indoor sowing
Foxglove grows easily from seed, and since the seed needs light to sprout, press it onto the surface and leave it uncovered. Sow indoors in late spring or direct sow in late summer or spring once frost passes, then thin seedlings to about 18 inches apart. Most plants form a leaf rosette the first year and flower the second, while first-year-flowering cultivars can bloom about 5 months from an early indoor sowing. Leave a few spikes standing and it reseeds itself freely.
Myths
Foxglove is behind modern heart medicine, so a little must be harmless or even healthy.
Foxglove is indeed where the heart drug digitalis came from, yet the raw plant is deadly. There is no safe home dose, because strength swings wildly from leaf to leaf and a small amount can throw the heart into a fatal rhythm. The pharmacy version is purified and measured to the microgram, and the garden plant never is.
Foxglove always lives exactly two years then dies.
A two-year clock is usual, with a leaf rosette the first year and a flower spike the second, but it is not fixed. Some cultivars bloom in year one, and cutting the stalks back before seed sets can stretch a plant into a short-lived perennial.