Taxonomy and origin
Foxglove is a group of about 20 species in the plantain family, Plantaginaceae, and the one behind nearly every garden spire is common foxglove, native to western Europe and Morocco. In the wild it takes woodland clearings, mountainsides, and above all disturbed ground, which is why it lines roadsides far outside its home range. It grows across the United States, wild in some places and planted in others. The genus name comes from the Latin digitus, meaning finger, for the shape of the flower, and the species name is Latin for purple, the color the plant produces most often. The English name says the same thing in plainer words, since a single bloom looks like the snipped off finger of a glove. Older country names stuck to it as well: purple foxglove, fairy gloves, fairy bells, and lady's glove, with dead man's bells kept alive in the poison literature.
Two shapes make the plant recognizable before the flowers even open. Low down sits a rosette of soft, downy leaves, and out of its center rises a leafy spire carrying a terminal raceme of large, pendulous, funnel shaped bells. The leaves are alternate and reach up to a foot long, gray white and downy on the upper surface, woolly or hairy below, and the clump they make stays low and close to the ground. The flowers hang from the stem and face downward, lined up along one side of it in the wild species and spiraled right around it in some cultivars. The records differ on how big a single bell is: the corolla runs 1.5 to 2.5 inches long, or 2 to 3 inches, depending on the source. Inside it carries long hairs and heavy dark purple spotting edged with white on the lower lip, which serves as a landing platform for pollinators. After pollination the flower is replaced by a rounded capsule that splits open at maturity and releases numerous small brown ridged seeds.
The plant reached medicine long before it reached most American gardens. William Withering published An Account of the Foxglove, and Some of Its Medical Uses in 1785, drawing on 156 of his own cases to demonstrate that the leaf worked against dropsy, the bodily swelling that came with heart failure. He recorded the two details that still describe the danger: the leaf preparations were effective in small, nontoxic doses, and their strength shifted with the plant's stage of bloom. Those leaves are still the source of the drug. Digitalis remains the active ingredient of digoxin and digitoxin, and digoxin itself is used to improve the pumping of a heart in congestive failure and to block the atrioventricular node when the atria run too fast.
Bloom time
Foxglove flowers in late spring and early summer, May to June in most American gardens, peaking about the time the first roses open. Each spike opens from the bottom upward, and a single spike can hold 20 to 80 flowers, so the top of the stem is still opening while the lowest bells have already gone over. The window itself is elastic. The main flush lands in early summer, a planting holding several ages of plant can carry bloom for several months from late spring onward, and in a cool growing season flowering continues right through the summer until frost. The season stretches at both ends. Extra flower stems appear later in the year on some plants, most often where the first stalks were removed after blooming. And the perennial yellow foxglove holds its spikes back to mid and late summer, so a bed carrying both keeps a spire standing from the roses through to the hottest weeks of the year.
Toxicity and pet safety
Every part of foxglove is poisonous. The flowers, leaves, roots, and stems all carry cardiac glycosides, naturally occurring chemicals that act on the heart, and any part of the plant can be deadly if it is swallowed. The poisonings on record begin the same way, with the plant going into a mouth: sucking the flowers, or eating the seeds, stems, or leaves. What follows is nausea, vomiting, diarrhea, stomach pain, severe headache, an irregular and slow pulse, tremors, unusual color visions, convulsions, and in the worst cases cardiac arrhythmias and death. The heart effects can be slow to show, since cardiovascular toxicity may be delayed up to 8 to 12 hours after the plant is eaten, so a person who feels fine an hour afterward is not yet clear of it. Do not induce vomiting. If you are certain that part of the plant was swallowed, go to the emergency room. A man gathering wild greens picked about 12 young foxglove leaves in mistake for borage and cooked them into a sauce; he and his wife spent 2 nights in the hospital and were still dizzy, with a low heart rate, for several days after they were sent home. Children are the group the warnings single out, since both the flowers and the seed capsules draw them in and every part of the plant is extremely poisonous.
For animals the listing is short and consistent: foxglove is toxic to dogs, cats, and horses, through the same cardiac glycosides, and the recorded signs are cardiac arrhythmias, vomiting, diarrhea, weakness, cardiac failure, and death. The Merck Veterinary Manual puts oleander and foxglove at the top of the cardiac glycoside plants for toxicity and adds that cats are believed to be more sensitive than dogs. Signs are expected within the first 2 hours after exposure and can persist for 4 to 5 days, and fatalities have been reported even where treatment was aggressive. The record splits on skin contact: NC State Extension lists the species as not causing contact dermatitis, though contact with the leaves can irritate sensitive skin.
Whether it has to come out of the garden depends on who uses the bed. The strict answer is on record and it is unqualified: do not plant or grow foxglove where children or pets play. That line is written for a plant standing within reach of a mouth, which is the exposure every poisoning case runs through. A border set back behind other planting, worked in gloves and followed by a hand wash, is a different proposition from a lawn edge patrolled by a puppy that chews whatever it finds. Where a child or an animal can reach the bells, take the strict answer. Where they cannot, foxglove is a border plant handled with gloves like any other. Gardeners who would rather not make the call at all get a similar vertical line from snapdragon.
Does foxglove come back every year?
Common foxglove is a biennial, which means it lives for two years. A rosette of foliage forms low to the ground in the first year, and the flower spike grows out of that rosette in the second, after which the plant is finished. Biennial foxgloves generally die once they have flowered, so a display every year means replacing them every year; skip a season of sowing or planting and the spikes turn up in alternate years with a blank one in between. The species does not always keep to the rule, and it has been recorded behaving like an annual, and in other cases like a herbaceous perennial. That variability is most of the confusion, because a plant bought in flower at a nursery is already in its second year, and its whole remaining life is that one summer. What comes back in most gardens is the next generation. One plant can produce 1 to 2 million seeds, and they self-sow readily where conditions suit them, so a colony holds its ground for many years and passes for a long lived perennial, in the way a hollyhock patch does. Careful gardens lose the plant for the opposite reason: the seedlings that were supposed to carry the planting forward get buried under fresh mulch or pulled out with the weeds, and the complaint that only one of three plants came back is a standing fixture of garden forums.
Some foxgloves are perennial in the ordinary sense. Perennial species live several years and can be divided every other year to stretch that further, though they are short lived even then, lasting only a few years more than the biennials do; individual yellow foxglove plants generally manage 4 or 5 years. A third group gets around the wait entirely, the strains bred to flower in their first year from seed, which most biennial foxgloves cannot do. Which of the three is in your pot is rarely printed on the label, and buyers say as much when the second year disappoints them. Deadheading is the last hope people pin on a biennial, and the record is mixed. Cutting all flowering stalks back to the basal foliage before seed sets can push a plant to act as a perennial, though it buys one more year of flower some of the time and nothing the rest, so keeping back-up plants is the safer plan.
Foxglove types and which ones come back
Color is the easy part: garden strains run from the wild purple through pink, peach, yellow, and white, and most keep the spotted throat. Life cycle is the part to check before you buy, since some of these flower in their first year from seed and others make you wait for the second. A card with no badge is a common foxglove cultivar on the biennial schedule.
Light
Morning sun with afternoon shade is the combination foxglove flowers best in. The published range around that is wide and covers almost everything: full sun through light shade at one end, dappled and even deep shade at the other. What the plant is really managing across all of it is moisture. Hot sun scorches the soft foliage, while most types will take a sunny position as long as the soil stays moist, and the woodlands and glades these plants come from are the setting the dappled shade advice describes.
Soil and pH
Moist, well-drained soil with plenty of organic matter in it is what foxglove asks for, and it must not be allowed to dry out. On acidity it leans one way: the preference on record is acid soil below pH 6.0, and moist, organically rich, acidic ground suits it best, although it grows easily enough in average, medium, well-drained soil in part shade. In practice it will take almost any soil that is neither too dry nor too wet. Bed preparation carries most of the work. Dig plenty of organic matter such as leaf mold or garden compost through the ground before planting and lay a thick mulch over the surface afterward, or amend with organic matter in a bed that already drains well. On poor soil, a yearly application of a balanced granular fertilizer helps. The perennial species fail at the two extremes, ground that dries out for long periods and ground that stays permanently wet.
Water
An established foxglove in soil rich in organic matter needs watering only during long dry spells in summer, and the overall requirement is rated medium. The plant signals for itself, since wilting large leaves are a good indicator that it wants a long soak. Newly planted foxgloves are the exception and need regular water for at least the first few months, until their roots have spread out into the surrounding soil; gardeners report new plants drooping while the ground still feels damp, which is what that rooting lag looks like. Containers dry out faster and need regular watering right through the growing season. Yellow foxglove, once established, is relatively drought tolerant.
Sowing and planting
Foxglove is raised from seed, and the seed needs light to germinate, so it is sown on the surface and left uncovered; press it onto the potting mix and leave it in the open. Outdoors that means a sheltered spot, an unheated greenhouse, or a coldframe; under cover it means uncovered seed in 72 to 128 cell trays. Seedlings raised inside go into the garden after the last spring frost. Plants bought in growth go in during spring or fall, when the soil is moist and warm enough to encourage new root growth. Small plug plants are the exception, since fall planting is not recommended for them; they come through better kept in their pots in a sheltered spot over winter, out of reach of slugs, then planted into the border in spring.
Most foxgloves will grow in a large container of loam-based peat-free potting mix, set in a sheltered spot in light shade, although roots in a pot are more exposed and more likely to take frost damage than roots in open ground. Staking is a judgment call. Tall varieties may need it to stay upright, though on sturdy stems in a sheltered spot out of strong winds it is unnecessary. In exposed sites, and on tall cultivars carrying larger blooms, a bamboo cane keeps the spike from snapping. Give the tallest plants a sheltered position from the start.
When to sow, and when it flowers
Which row applies depends on whether you want spikes next year or this one, and on whether the seed starts under cover or goes straight into the ground.
Height and spread
A foxglove in flower stands 2 to 5 feet tall and 1 to 2.5 feet across. Most spikes land in the middle of that band, since 3 to 4 feet is the normal height for the species and the spires are usually 2 to 4 feet, reaching 5 only infrequently. Cultivars pull the range wide at both ends, from 2 to 3 feet up to 5 to 6 feet, so the height printed on the packet matters more here than it does for most border plants. Take in the whole genus and the range is wider still, running from spikes of 1 foot to spikes of 8 feet or more. The width figure describes the leafy base, since the flower stem itself occupies almost no ground, which puts foxglove at the back of a border in the same rank as lupine.
USDA hardiness
Foxglove is hardy through USDA zones 4 to 9, and the finer listings agree, running 4a to 9b. The disagreement to know about sits at the warm end, where Missouri Botanical Garden stops the range at zone 8 and Clemson carries it to 9, which leaves gardeners in zone 9 growing a plant at its published limit. Within the range the species is hardier than some of the plants sold under its name, because certain varieties are hardy only to zone 5. The perennial species vary more again: several of them come from warmer climates, are not fully hardy, and want a mild sheltered position, winter protection, or both.
What to do after flowering
The cut you make when the main spike goes over decides what the plant does for the rest of the summer, and what to do with the finished plant after that is one of the standing questions on garden forums. Take the central spike out and more spikes follow it, and the cleanest version of that cut removes the whole flower stem at the base as soon as the flowers finish, which keeps the plant's energy out of seed production. The same cut ends the next generation, so a garden that wants young plants every year has to leave a few stems standing to set seed. Both halves belong together: deadhead after flowering to avoid excessive numbers of seedlings, and let some flowers form seed so the population persists. The plant itself is a separate decision. A foxglove looks ragged once it has finished, and there is no obligation to keep it in the bed. The remaining tidy-up waits for early spring, when winter damage, yellowing leaves, and old seedheads all come off together. Yellow foxglove takes the opposite handling in fall, because its foliage tends to stay evergreen: cut any remaining flower stems down to the base, leave the leaves alone through winter, then prune off whatever the cold damaged in spring. Removing its flower stalks as the blooms fade promotes reblooming, and leaving a few of them is how it sows itself.
Leaves but no flowers
A foxglove making leaves and no spike is usually doing what it is supposed to do, and these checks separate the plant that is waiting from the plant that is failing.
Pests and diseases
Foxglove has few pest problems, and deer and rabbits are not among them. Both animals usually walk past the plant because every part of it is toxic, and it is listed as deer resistant on the grounds that it contains a chemical deer avoid. What does go wrong is mostly fungal and mostly seasonal. Powdery mildew can infect the foliage in late summer, and left untreated, powdery mildew and leaf spot together depreciate the leaves considerably by early to mid-summer; mildew on its own is usually survivable, since plants generally recover from it without treatment. The insect list is short: aphids, mealy bugs, slugs, and Japanese beetles, with fungal diseases named beside them. Aphids colonize the developing flower spikes and can usually be washed off with a hose, taking care not to damage the stem. One problem gets misread often enough to name, since leaf and bud eelworms damage the leaves in a way that is easily confused with weather damage or fungal leaf spots.
What actually goes wrong, ranked
Across fifty-nine foxglove threads on garden forums and extension question boards, four clusters take most of the traffic, ranked below by how often each came up, with two smaller complaints that keep recurring underneath them.
Twelve of the fifty-nine threads, the biggest single worry. Cat and dog owners in particular ask whether the plant has to come out of the garden entirely.
Twelve threads. The repeated failure happens indoors, where seed germinates well and the seedlings collapse as soon as the cover comes off.
Ten threads, and the extension answers point at overwatering and lost roots.
Nine threads asking why the plant failed to return, or whether what they had was a biennial or a perennial.
Seedlings are stripped before the plants are large enough to survive it.
Tall spikes lean or fall, and posters find that the advice they get on staking contradicts itself.
Bumblebees and hummingbirds
Bumblebees and hummingbirds are the visitors, both drawn by the nectar, and hummingbirds are recorded at the flowers alongside the bees. Nothing on record ties that nectar to harm in either of them. The nectar itself sits in a ring at the base of each flower tube. A bumblebee climbs deep inside to reach it and rubs against the anthers lying flat on the upper inside surface on the way through. The spotted throats are part of the same mechanism, guiding pollinators to the nectar deep inside the individual flowers.
Propagation and longevity
Seed is the recommended way to propagate foxglove, and for most plants in this genus it is the only route that matters. The perennial species offer two alternatives. Yellow foxglove can be divided in spring or fall by separating new sections from the crown, and off-shoots taken from around the base in spring give plants genetically identical to the parent. Seed is not equally dependable across cultivars, since some of them produce very few viable seeds, which is the reason to collect and sow plenty. The strawberry hybrid needs planning around, because it is recorded behaving two different ways: dying after flowering and setting no seed, or coming true from seed and blooming for several years. Where it does not seed, replacement means buying new plants or commercial seed. Yellow foxglove sows itself under favorable conditions without becoming aggressive about it.
In the vase
Foxglove spikes are cut for bouquets, and the yellow species makes a good cut flower when the blooms are picked half open. Growers who want the straight upright spike that arrangers ask for tie the stem to a support while the plant is still standing in the bed.
Foxglove myths, settled
Foxglove attracts more folklore than most border plants, and these claims come up often enough to settle.
The myth: One leaf is enough to kill a grown man.
The reality: The poison references and the clinical record differ in emphasis here. Any swallowed part is listed as possibly deadly, while the follow-up on real poisonings records symptoms lasting 1 to 3 days, sometimes with a hospital stay, and death as unlikely. Both point the same way for a household: a swallowed part is an emergency.
The myth: Foxglove tea is an old heart remedy worth trying.
The reality: Eating any part of the plant or making tea from the leaves amounts to taking an unregulated dose of heart medicine, which can slow the heart or make it irregular. The plant was used against heart conditions and is highly poisonous when used incorrectly.
The myth: Foxglove is invasive everywhere in the United States.
The reality: It is invasive in some places, among them the Pacific Northwest and Aoraki Mount Cook National Park in New Zealand, which is a shorter list than the reputation suggests.
The myth: Slugs leave foxglove alone because the whole plant is poisonous.
The reality: Slugs and snails are fond of foxglove seedlings, and the young rosettes are stripped before the plants are big enough to shrug it off.
What to expect from year to year
Three seasons stand between a sown seed and a patch that runs itself, and only the middle one has flowers in it.
Year one is leaves. A seed sown in spring produces only a basal rosette, and that rosette overwinters as evergreen foliage. It looks nothing like the plant on the packet, and nothing done to it in its first summer brings the flower forward.
Year two is the spike. Slender flower spikes rise from the rosette the following spring and bloom in late spring to early summer. Left standing, they self-seed readily, which is where the next plants come from. By late summer the plant is scraggly, and because it is a biennial it can be pulled as soon as it has released its seed.
Year three is the seedlings. They come up close to the parent plant in spring, in numbers, and while they are still small they move easily, so this is the point at which the patch gets arranged by hand. One group skips the sequence entirely, the strains bred to flower in the year they are sown: 'Foxy' was the first variety to do it, and the 'Camelot' series joined the list later.
Flower photos
FAQ
Is foxglove poisonous to touch?
The danger is in swallowing it, not in handling it. Gloves are advised for handling plants and seed all the same, and washing your hands when you come in from the garden is the standing advice for any plant you are not sure of.
What does foxglove do to a person who eats it?
Stomach upset is the most common effect, alongside visual symptoms that classically appear as a yellow-green discoloration and heart symptoms such as palpitations, breathlessness, and fainting. Some people see yellow, green, or white halos around objects.
Can I have foxgloves in a yard with dogs?
Not where a dog can get at them. Foxglove is flagged as a problem for dogs, cats, horses, and children, and plants carrying cardiac glycosides have a narrow margin of safety. A dog that has chewed any part of one needs a vet, and digoxin-specific antibody fragments work as an antidote for plant cardiac glycoside poisoning as well as for the drug.
How dangerous is foxglove for a small child?
Poison severity for the species is rated high. Plant ingestions account for 80 percent of pediatric exposures to this class of poison, and medicines account for the other 20 percent.
Are foxglove seeds poisonous too?
Yes. The poisonous ingredients, named as deslanoside, digitoxin, and digitalis glycoside, sit in the flowers, leaves, stems, and seeds. Both the flowers and the seed capsules draw children in, so collect seed in gloves and keep the capsules out of reach.
Which foxgloves are true perennials?
Yellow foxglove, straw foxglove, rusty foxglove, strawberry foxglove, and the Illumination Series make up the perennial side of the genus. Their spikes are more modest than the biennial types and they live a little longer, in hues such as soft yellow, rusty orange, or dusky pink.
Are foxgloves bad for hummingbirds?
No source records harm to them. Hummingbirds are listed among the pollinators the flowers attract, and they are recorded feeding at them alongside the bumblebees.
Is every foxglove poisonous, or only the purple one?
All of them. Every species and hybrid in the genus is highly toxic and none of it should ever be eaten, so a yellow or a rusty perennial gets handled the same way as the purple biennial.
How do I know the plant in my border is a foxglove?
In its first year it is a low rosette of hairy leaves that reach 10 to 12 inches long. In its second it carries tubular bells in white, pinks, and purple, spotted inside the petals.
Interesting tips
- Every so often the top flower on a spike opens out fully and faces forward, flat and round like a small satellite dish. The mutation is called terminal peloria, and it turns up only occasionally.
- The perennial side of the genus has selections of its own to hunt for: 'John Innes Tetra' stands about 2 feet with rose colored flowers and 'Spice Island' reaches 3 to 4 feet in yellow-orange on tall sturdy stems.
Related Guides & Flowers
Hollyhock
The other cottage spire that holds its ground by seeding itself, a patch that outlives any single plant.
Delphinium
The tall early summer spire gardeners plant beside foxglove, with the same argument about staking.
Snapdragon
A shorter garden spike that flowers in its first summer, for the same upright shape in a smaller bed.
Purple flowers
Where foxglove sits among the other purples, if color is what you are planting for.