Ornamental · Plantaginaceae
Foxglove
Digitalis purpurea
Tall spires of speckled bells rise over a 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
A foxglove in flower lifts a tall, one-sided spike crowded with speckled tubular bells, each one wide enough for a bee to climb inside. It settles into a part-shade border or woodland edge, sends out acid-loving roots, and wants steady moisture. The bells span from the wild plant's deep purple to the white, cream, and rose of garden strains.
Most foxgloves are biennial. The first year stays low as a flat leaf rosette. The second year the rosette throws up a flower spike, sets seed, and fades. A spike or two left to ripen drops seed and self-sows, so the planting renews itself generation to generation.
That beauty hides a serious catch. Foxglove is the source of the heart drug digitalis, and every part is poisonous to people and animals, so it belongs only where children, pets, and grazing animals cannot reach it.
Care
The short version: Foxglove wants dappled part shade, evenly moist acidic soil, light feeding, and air moving through its leaves. Deadheading the spent spikes brings a second flush. Every part is poisonous to people and animals.
Light
Foxglove looks its best in partial shade, the dappled light along 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 tall spikes from drooping.
Water
The soil should stay evenly moist, watered every 3 to 7 days depending on heat and rain. Let it dry out and drought stress trims the flower count, so a mulch layer to hold moisture earns its place.
Soil
Foxglove sinks its roots into moist, well-drained ground that is rich in organic matter. It leans acidic, around a pH of 5.0 to 6.0, so dig in compost and leave the lime out.
Humidity
Average humidity suits it, and plain outdoor air asks for nothing extra. Airflow between plants is the real concern, since still, damp air around crowded leaves invites powdery mildew.
Feeding
Foxglove is not a heavy feeder. A balanced fertilizer or compost worked into organically rich soil, given seasonally through the growing season, keeps it fed.
Pruning
Cut the spent flower spikes after bloom to encourage a secondary bloom and rein in heavy self-seeding, leaving a few standing if the planting should persist. Trimming the flowering stalks back to the basal foliage before seed sets pushes plants toward acting as short-lived perennials.
Size & spacing
The plant stands 2 to 5 feet (61 to 152 cm) tall with a spread of 12 to 30 inches (30 to 76 cm). Set the rosettes about 18 inches apart so air slips through and leaves dry quickly.
When to plant
Foxglove holds a slow two-year rhythm. Seed is scattered on the surface in late spring or sown straight into the ground in late summer, young plants go out after the last frost, and the tall flower spikes push 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
Foxglove is easy, but damp, crowded conditions invite a few fungal problems and the usual garden insects. The first marks appear on the leaves and crown, and catching them early lets you step in before anything spreads.
Plant wilts, base of stem rots, and plant collapses
A soft, mushy, discolored crown and roots sitting in soggy ground point to crown rot, which takes hold in poorly drained or waterlogged soil. The damage is severe, and once the crown goes soft the plant cannot be saved, so lift and destroy it, fix the drainage before replanting, and stay out 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
A dusty white film on the leaves marks powdery mildew, while discrete brown or tan lesions mark a leaf spot fungal disease, both helped by crowding and poor air circulation. Strip off and discard the marked leaves, open the spacing to about 18 inches apart, and water at the base so the foliage stays dry.
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
Tight knots of aphids and mealybugs suck sap along the stems and leaf undersides, while Japanese beetles or slugs gnaw the foliage and leave slime trails and ragged holes. A hard jet of water dislodges aphids, beetles and slugs come off by hand, and a clinging infestation gives way to insecticidal soap. Clearing the garden debris that hides slugs cuts the trouble back.
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
Dry soil and a plant gone limp through hot, dry spells signal drought stress, and the bloom count falls with it. Steady watering holds the soil evenly moist while mulch keeps that moisture from escaping, since soil left to dry out is what limits flower production.
Fix:
- Water consistently to keep soil evenly moist
- Mulch to conserve soil moisture
Toxicity
Treat the plant as dangerous. Every part holds cardiac glycosides, the same compounds behind the heart drug digitalis, and even a small amount can trigger 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 away from 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
Cats: severe. Even a single nibble is dangerous, as cardiac glycosides bring drooling and vomiting, then a slow or wildly irregular heartbeat that can stop the heart, so any chewing counts as an emergency.
Dogs Severe
Dogs: severe. A dog that swallows any part may vomit, have diarrhea, and weaken before the heart rhythm turns dangerous, with collapse and death able to follow, so reach a vet right away.
Horses Severe
Horses: severe. Foxglove in pasture or hay poisons them gravely, bringing on colic, a staggering gait, and a heartbeat that races or stutters toward heart failure.
Rabbits Severe
Rabbits: severe. The same heart toxins strike them hard, leaving them limp and off their food at real risk of sudden heart failure, so a rabbit must never reach the leaves.
Livestock Severe
Livestock: severe. Cattle, sheep, and goats are poisoned by the plant fresh or dried in hay, showing drooling, gut upset, weakness, and fatal rhythm changes, and dried plants stay just as deadly.
Birds Severe
Birds: severe. Cardiac glycosides are toxic to them too, so keep poultry and pet birds well clear of every part.
People Caution
People: 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 purple, but garden strains widen the range, and several were bred to flower in their first year. These are worth knowing.
Foxy
Foxy is a compact strain topping out around 2 to 3 feet, its bells 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 hung with yellow tubular flowers brushed with brown markings.
How to propagate
Foxglove is grown from seed. 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 because the seed needs light to sprout, it is pressed onto the surface and left uncovered. Sow it indoors in late spring or straight into the ground in late summer or spring after frost passes, then thin the seedlings to about 18 inches apart. Most form a flat leaf rosette the first year and send up a spike 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, but the raw plant is deadly. No safe home dose exists, 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.
A two-year clock is the usual pattern, 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.