Ornamental · Plantaginaceae
Foxglove
Digitalis purpurea
Tall spires of speckled bells brighten a shady border, but 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 hung with speckled tubular bells that bees climb right inside. This is a plant for a part-shade border or woodland edge, where its acid-loving roots get steady moisture. Colors run from the wild plant's purple all the way to white, cream, and rose in the garden strains.
Most foxgloves are biennial, so the first year is just a low leaf rosette. The second year it sends up a flower spike, sets seed, and fades. Leave a spike or two to ripen, though, and it self-seeds so the planting keeps rolling on generation to generation.
All that beauty comes with a serious catch. Foxglove is the source of the heart drug digitalis, and every part of it is poisonous to people and animals. Grow it only where children, pets, and grazing animals can't reach it.
Care
The short version: give foxglove partial shade, keep the soil evenly moist on a watering rhythm of every 3 to 7 days, and plant it in acidic, organic ground around pH 5.0 to 6.0. It is easy to grow, but toxic to people and pets, so site it where curious hands and grazing animals can't get to it.
Light
Foxglove is happiest in partial shade, the kind of dappled light you'd find at a woodland edge. It can take full sun where summers stay cool and moist, but in hot regions a few hours of afternoon shade keep the spikes from wilting.
Water
Keep the soil evenly moist and water about every 3 to 7 days depending on heat and rain. Don't let it dry out, since drought stress cuts down on flowers, and a layer of mulch goes a long way toward holding that moisture in.
Soil
Give it moist, well-drained soil that's rich in organic matter and on the acidic side, ideally a pH of 5.0 to 6.0. Work in some compost when you plant, and skip the lime so the ground stays acid.
Humidity
There's no humidity number to chase here, since ordinary outdoor air suits foxglove fine. What really counts is airflow between plants, because still, damp air around crowded leaves is exactly what powdery mildew likes.
Feeding
This is not a hungry plant. A balanced fertilizer or some compost worked into rich soil carries it through the growing season, and seasonal feeding is plenty.
Pruning
Deadhead the spent spikes after bloom to nudge a second flush and keep self-seeding in check, but leave a few standing if you want the planting to persist. Cutting the flowering stalks back to the basal foliage before seed sets can coax plants into acting like short-lived perennials.
Size & spacing
Expect a height of 2 to 5 feet (61 to 152 cm) and a spread of 12 to 30 inches (30 to 76 cm). Set plants about 18 inches apart so air can move through and the leaves stay dry.
When to plant
Foxglove works on a slow two-year clock. You surface-sow seed in late spring or direct sow in late summer, move young plants outdoors after the last frost, and then the tall flower spikes show up the following 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
Good news: foxglove is easy. The catch is that damp, crowded conditions open the door to a few fungal issues and the usual garden bugs. Spot the early signs on leaves and crown and you can step in before anything spreads.
Plant wilts, base of stem rots, and plant collapses
That collapse is crown rot, which takes hold in soggy or poorly drained ground. Check the crown and roots: if they're mushy and discolored in wet soil, the plant is done. Remove and destroy it, fix the drainage before you replant, and steer clear of low, waterlogged spots. Once the crown goes soft, there's no saving it.
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 usually points to powdery mildew or a leaf spot fungal disease, both encouraged by crowding and stale air. A white powdery film means mildew, while distinct brown or tan lesions mean leaf spot. Pull and toss the affected leaves, open up the spacing to about 18 inches apart, and water at the base rather than over the top so foliage stays dry. It's a setback, not a disaster.
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
Two different culprits are at play. Sap-sippers like aphids and mealybugs gather on new growth, while Japanese beetles or slugs chew the foliage. Check stem tips and leaf undersides for the small bugs, and watch for beetles, slime trails, or ragged holes. Blast aphids off with a strong jet of water, hand-pick the beetles and slugs, and reach for insecticidal soap if an infestation just won't quit.
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
Fewer blooms and a limp look during hot, dry spells usually trace back to drought stress from the soil drying out. The fix is steady watering to hold even moisture, plus a mulch layer to keep that moisture from escaping. Don't let the ground dry out, since drought stress directly trims flower production. This one is purely cosmetic.
Fix:
- Water consistently to keep soil evenly moist
- Mulch to conserve soil moisture
Toxicity
Here's the part you can't skip: treat foxglove as genuinely dangerous. Every part carries cardiac glycosides, the same 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 mistook the leaves for an edible herb. Keep it well away from children, pets, and grazing animals, and don't leave cut spikes sitting in vase water within reach.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Severe
Cats: even a nibble is dangerous. The 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
Dogs: a dog that eats any part may vomit, get diarrhea, and grow weak before its heart rhythm turns dangerous. Collapse and death can follow, so get to a vet right away.
Horses Severe
Horses: foxglove in pasture or hay leaves a horse gravely poisoned, with colic, a staggering gait, and a heartbeat that races or stutters toward heart failure.
Rabbits Severe
Rabbits: the same heart toxins hit rabbits 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
Livestock: cattle, sheep, and goats are poisoned by the plant whether it's fresh or dried in hay, showing drooling, gut upset, weakness, and fatal rhythm changes. Dried plants stay just as deadly.
Birds Severe
Birds: cardiac glycosides are toxic to birds too, so keep poultry and pet birds well clear of every part.
People Caution
People: no part of foxglove is food. People have been poisoned mistaking the leaves for comfrey, and eating any of it, or even drinking water from a vase of cut spikes, can set off vomiting and a dangerous heartbeat. 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 range wider, and a handful were bred to flower in their first year. Those 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 you sow it 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 out a second season.
Temple Bells
Temple Bells is a dwarf type carrying yellow tubular flowers brushed with brown markings.
How to propagate
Foxglove is grown from seed, and honestly 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
Grow it from seed, which is easy. The seed needs light to sprout, so press it onto the surface and leave it uncovered. Sow indoors in late spring or direct sow in late summer or spring once frost has passed, then thin the seedlings to about 18 inches apart. Most plants make a leaf rosette the first year and flower the second, though 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.
Yes, foxglove is where the heart drug digitalis came from, but the raw plant is deadly. There's no safe home dose, because the strength swings wildly from one leaf to the next and a small amount can throw the heart into a fatal rhythm. The pharmacy version is purified and measured to the microgram; the garden plant never is.
Foxglove always lives exactly two years then dies.
It usually runs on a two-year clock, a leaf rosette the first year and a flower spike the second, but that isn't locked in. Some cultivars bloom in year one, and cutting the stalks back before seed sets can stretch a plant into a short-lived perennial.