Ornamental · Plantaginaceae
Beardtongue
Penstemon digitalis
Given full sun and sharp drainage, this hardy native throws up tall spikes of white tubular bloom the bees work over.
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 in the figwort family, sending up slender upright stems from a low rosette. From late spring into early summer those stems carry tall spikes lined with white, two-lipped tubular flowers, each bloom flaring open at the mouth where bees and the occasional hummingbird push inside. The common name foxglove beardtongue traces that tubular flower shape, not any tie to true foxglove.
The plant is built lean and tough. It weathers cold to -29°F (-34°C), its established roots ride out dry spells, and its fast growth throws up fresh stems quickly enough to fill a gap within a season. Sun on the foliage and ground that drains are the whole of what it wants.
One trait shapes how it grows over time: it widens. Beardtongue self-seeds, and each year the crown thickens and the clump pushes outward, so it creeps past its first footprint. Deadheading the spent spikes and a division every few years hold that spread in check.
Care
The short version: full sun and sharp drainage are the whole game. Water moderately while the roots take hold, then let it ride dry spells, feed it next to nothing, and lift and divide the clump every 2 to 3 years to keep the spikes coming.
Light
Beardtongue flowers heaviest in full sun, where the flower spikes hold upright and pack the stems with bloom. In partial sun or light shade it still grows, but the stems stretch looser and set fewer flowers.
Water
Water moderately while the roots take hold, letting the top half of the soil dry between drinks, roughly every 7 to 14 days. Once settled it shrugs off drought, and the sharper danger runs the other way, since wet or poorly drained soil rots the roots from below, so keep the ground on the dry side.
Soil
The roots run happily through loam, clay, or sand as long as water drains away fast. Aim for a pH between 5.5 and 7.0, and note that sharp drainage counts for far more here than rich, dark earth.
Temperature
This cold-hardy native holds its crown through winters down to -29°F (-34°C) and takes summer heat up to around 86°F (30°C). That span carries it across a wide stretch of the country with no wrapping or shelter.
Humidity
Ordinary outdoor air suits the foliage, so there is no figure to chase. Moving air over the leaves matters more than moisture in the air, because still, crowded growth is what lets leaf spot mark the surface.
Feeding
A native that thrives on lean ground, beardtongue draws little from the soil and needs almost no feeding. A light spring dose of balanced fertilizer or a little compost is plenty, and richer feeding only leaves the tall stems floppy.
Pruning
Snip the spent flower spikes through the season to keep the plant trim and to curb its self-sowing. Cut the foliage back to the ground in late fall or early spring so fresh shoots have clear room to rise.
Repotting
Beardtongue grows in open ground rather than a pot, yet the crown wants regular renewal. Divide the clump every 2 to 3 years to keep it vigorous, reading thinning bloom or a bare, dying center of the clump as the cue.
Size & spacing
In bloom the stems reach 2 to 4 feet (60 to 120 cm) tall over a leafy clump 18 to 24 inches (45 to 60 cm) wide. Set plants that far apart so air slips between the stems and leaf spot finds no hold.
When to plant
Beardtongue runs on a cool-season rhythm written into its seed. That seed needs a cold, moist chill before the first green shoot breaks, so it sows outdoors in fall or starts indoors in late winter after stratifying, the young plants set out in spring once frost has passed, and the white spikes rise 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 meets few real enemies, and the troubles it does show nearly all trace to soggy soil or a crown that has outgrown its patch. Match what you see on the stems, leaves, and roots below, and act early while the fix still bites.
Wilting plant with a blackened base and mushy roots
When the stems slump and their bases darken to black while the roots turn brown and soft, the trouble is root or crown rot. Wet soil sets it off, most often across winter, and beardtongue withstands dry ground far better than a waterlogged bed. A raised, free-draining spot turns it around, and the collapsed, rotted tissue lifts away.
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 self-seeds and thickens its clump, so the crown creeps outward and fresh seedlings crop up until it presses on its neighbors. Snipping the faded spikes before the seed ripens cuts off the source, and stray seedlings pull free of the soil. Lifting and splitting the crown every few years pares it back to its footprint.
Fix:
- Remove unwanted seedlings
- Deadhead before seed set to limit self-sowing
- Divide and thin the clump
Spots and blotches scattered across the leaves
Small discolored specks and blotches breaking the smooth green surface of the leaves are fungal leaf spot, an occasional and skin-deep flaw. The blemished leaves lift off cleanly and the plant keeps its stride. Moving air is the real cure, so open spacing and dry foliage hold it off.
Fix:
- Remove and dispose of affected leaves
- Improve air circulation and avoid overhead watering
Toxicity
The safety picture is clear: beardtongue is harmless. For all the foxglove in its common name, not a leaf, stem, or white flower on it carries true foxglove's poison, and it sits on no toxic plant list, so it is safe around cats, dogs, livestock, and children.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Beardtongue is safe for cats, since not a leaf or petal on it holds a toxic compound. A curious mouthful of the foliage brings no poisoning.
Dogs None
Dogs come to no harm from this plant. A big helping of the leaves might unsettle a stomach on bulk alone, but no toxin lurks in the tissue.
Horses Safe
Horses are unharmed by beardtongue. Its stems and leaves carry none of the cardiac toxicity that fills true foxglove.
Rabbits Safe
Rabbits can crop the leaves and flowers safely. Nothing in that soft green growth would poison them.
Livestock Safe
Cattle, goats, and sheep graze this plant without harm. Its foliage carries no toxin listed against livestock.
Birds Safe
Birds are safe among the foliage and the ripe seed. The tubular flowers pour out nectar for pollinators and pose no threat.
People Safe
Beardtongue is harmless to people, children included. The name echoes foxglove, yet its white flowers hold none of that plant's poison.
Generally safe around pets and people; no special handling required.
Varieties
Most gardens grow either the plain wild species or one cultivar prized for the deep color in its leaves. These are the two worth telling apart.
Husker Red
Named the 1996 Perennial Plant of the Year, this selection unfurls maroon-red leaves in spring that fade toward green as the season wears on while the maroon veining and red stems stay vivid.
Foxglove Beardtongue (species)
The straight species lifts tall clusters of white, two-lipped tubular flowers along its spikes from late spring into early summer.
How to propagate
Beardtongue multiplies without fuss, whether you split the crown of an established clump, sow the ripe seed, or root summer cuttings to hold a favorite cultivar's leaf color true.
DivisionEasy
Spring · One growing season
Splitting the crown is the plainest way to make more beardtongue and to keep the clump dense. In spring, every 2 to 3 years, the clump lifts from the soil and pulls apart into rooted pieces, and each piece knits back into the ground 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 breaks dormancy best after a cold, moist chill with light reaching it. Sown outdoors in fall, it takes the winter cold in the ground, or it can be chilled and started in late winter, with the first white spikes rising the following year.
Stem cuttingsModerate
Summer · Several weeks to root
Softwood cuttings snipped in summer hold a named cultivar's leaf color true, which seed cannot pass on. The cut stems set roots over several weeks before they are firm enough to pot on.
Myths
Foxglove beardtongue is poisonous like foxglove because of its name.
The name is the only thread tying these two plants together. Penstemon digitalis sits in a separate genus and holds none of the cardiac glycosides that make true foxglove dangerous. It appears on no toxic plant list and is safe around pets and people.