Ornamental · Plantaginaceae
Beardtongue
Penstemon digitalis
Give it full sun and sharp drainage, and this tough native throws up white spikes the bees can't get enough of.
Full sun
Every 7–14 days
USDA 3–8
2–4 ft · 0.6–1.2 m
Overview
Beardtongue is a clump-forming native perennial from the figwort side of things, and it really pulls its weight in a sunny border. From late spring into early summer, it sends up tall spikes of white, two-lipped tubular flowers that stay busy with bees and the odd hummingbird. And that common name, foxglove beardtongue? It's about the flower shape, not about being related to true foxglove.
The best part is how little it asks of you. It laughs off cold down to -29°F (-34°C), keeps going through dry spells once it's rooted in, and grows fast enough to fill a gap in one season. Give it sun and ground that drains, and it pretty much runs itself.
There's one habit worth keeping an eye on, though: it likes to spread. Beardtongue self-seeds, and the clump gets wider every year, so it can drift past the spot you picked for it. But a little deadheading and a division every few years keeps it right where you want it.
Care
The short version: full sun and sharp drainage are really the whole deal. Water moderately while it's settling in, then let it ride out dry spells, feed it almost nothing, and lift and divide the clump every 2 to 3 years to keep the blooms coming.
Light
Beardtongue flowers best in full sun, where the spikes stand up straight and bloom hard. It'll put up with partial sun or light shade too, but then it grows a bit looser and gives you fewer flowers in return.
Water
While it's settling in, water it moderately and let the top half of the soil dry between drinks, which usually lands around every 7 to 14 days. Once it's established it handles drought just fine, and honestly the bigger risk is the other way around, since wet or badly drained soil rots the roots, so when in doubt, keep it on the dry side.
Soil
It's not picky about soil and grows in loam, clay, or sand as long as the drainage is good. Shoot for a pH between 5.5 and 7.0, and keep in mind that sharp drainage matters way more here than rich soil does.
Temperature
This is one tough, cold-hardy native that takes winters down to -29°F (-34°C) and summer heat up to around 86°F (30°C). That range covers a big chunk of the country, no special protection needed.
Humidity
Average outdoor humidity suits it just fine, so there's no number to chase. Air movement matters more than moisture in the air, since still, crowded conditions are exactly what let leaf spot get started.
Feeding
As a native that does great on lean ground, beardtongue barely needs feeding. A light spring dose of balanced fertilizer or a bit of compost is plenty, and feeding it richly just makes it floppy.
Pruning
Deadhead the spent flower spikes through the season to keep it tidy and to rein in the self-sowing. Then cut the foliage back in late fall or early spring to make room for fresh growth.
Repotting
Beardtongue lives in the ground, not a pot, but it still wants a regular refresh. Divide the clump every 2 to 3 years to keep it going strong, and let fading bloom or a crowded, dying center be your signal it's time.
Size & spacing
In flower, plants hit 2 to 4 feet (60 to 120 cm) tall and settle into a clump 18 to 24 inches (45 to 60 cm) wide. Space them with that width in mind so air moves through and leaf spot stays away.
When to plant
Beardtongue works on a cool-season clock. Its seed needs a cold, moist chill before it'll sprout, so you sow it outdoors in fall or start it indoors in late winter after stratifying, then set plants out in spring once the frost's gone, and watch for those white spikes from May to July.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Late winter after 1-3 months cold-moist stratification
- Plant: Spring after last frost
- Harvest: May to July
Hardiness
USDA hardiness zones: 3–8
Temperature: down to -40°C
Troubleshooting
Beardtongue doesn't run into much trouble, and when it does, it usually comes back to wet soil or a clump that's gotten too big for its spot. Find what matches your plant below and jump on it early, while a fix still does some good.
Wilting plant with a blackened base and mushy roots
What you're looking at is root or crown rot, and it almost always comes from soil that stays too wet, usually over the winter. Here's the thing: beardtongue would much rather be dry than soggy, so more water is the last thing it needs. Move it somewhere raised that drains well, and clear out whatever has already gone soft.
Fix:
- Improve drainage by amending soil or relocating to a raised, well-drained site
- Reduce watering and avoid wet winter soils
- Remove and discard severely rotted plants
Plant creeping past its spot and crowding neighbors
Beardtongue likes to self-seed and widen its clump, so in a comfy garden it'll happily wander past the spot you had in mind. The trick is to snip the spent spikes before they set seed, which slows the self-sowing, and then just pull out any seedlings you didn't ask for. Dividing the clump every few years keeps the whole thing in check.
Fix:
- Remove unwanted seedlings
- Deadhead before seed set to limit self-sowing
- Divide and thin the clump
Spots and blotches scattered across the leaves
Those marks are just fungal leaf spot, which pops up now and then and is really only a cosmetic thing. Pick off the leaves that are spotted and the plant keeps right on going. Want it gone for good? Give it more air and try not to splash the leaves when you water.
Fix:
- Remove and dispose of affected leaves
- Improve air circulation and avoid overhead watering
Toxicity
Good news here: beardtongue is safe. Even with foxglove in its name, it doesn't carry any of true foxglove's poison and it's on no toxic plant list, so it's fine around cats, dogs, livestock, and curious kids.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Cats are totally fine around beardtongue, since there aren't any toxic compounds in it. Even a curious nibble won't cause any poisoning.
Dogs None
Dogs can hang out near this plant with nothing to worry about. Sure, a big mouthful of any plant might upset a stomach, but there's no actual toxin here.
Horses Safe
Horses won't be harmed by beardtongue at all. It just doesn't have the cardiac trouble you'd find in real foxglove.
Rabbits Safe
Rabbits can nibble away safely. There's nothing in the leaves or flowers that would poison them.
Livestock Safe
Cattle, goats, and sheep are all good grazing near this one. It's not on any list of things that are toxic to livestock.
Birds Safe
Birds are safe around the foliage and the seed. The plant even offers nectar to pollinators, and it's no threat to them either.
People Safe
People, kids included, have nothing to fear from beardtongue. The name winks at foxglove, but it doesn't share any of that plant's poison.
Generally safe around pets and people; no special handling required.
Varieties
Most gardens go for either the wild species or one standout cultivar that people love for its dark foliage. Here are the two worth knowing.
Husker Red
This one grabbed the 1996 Perennial Plant of the Year title thanks to its maroon-red spring leaves, which turn greener with age but keep that maroon veining and those red stems.
Foxglove Beardtongue (species)
The plain wild form gives you tall clusters of white, two-lipped tubular flowers from late spring right into early summer.
How to propagate
Beardtongue is easy to make more of, whether you split an established clump, sow the ripe seed, or root a few summer cuttings to keep a favorite cultivar true.
DivisionEasy
Spring · One growing season
Dividing is hands down the easiest way to get more beardtongue while keeping the parent clump strong. Just lift and split it in spring every 2 to 3 years, and each piece settles back in over a single growing season.
SeedModerate
Fall sow outdoors or stratify and sow late winter · Germinates best with cold-moist stratification and light; blooms typically the following year
The seed ripens in fall and really wants a cold, damp chill plus a bit of light before it'll sprout. So sow it outdoors in fall and let winter handle the chilling, or stratify it and start it in late winter, and you'll usually see the first blooms the following year.
Stem cuttingsModerate
Summer · Several weeks to root
If you're after a named cultivar, take softwood cuttings in summer, because seed won't hold that foliage color. Give the cuttings several weeks to root, and then they're ready to pot on.
Myths
Foxglove beardtongue is poisonous like foxglove because of its name.
Honestly, the name is the only thing these two plants have in common. Penstemon digitalis sits in a whole different genus and doesn't carry any of the cardiac glycosides that make real foxglove dangerous. It's on no toxic plant list and it's safe around pets and people.