Foxglove beardtongue

Sun

Full sun to light partial shade; flowering and stem strength are best in sun.

Water

Moderate while establishing. Established plants tolerate short dry spells, but flower best with some moisture during spring growth.

Soil

Average, well-drained soil, including loam and clay that does not remain waterlogged; tolerates a broad pH range.

Height

3-5 ft (0.9-1.5 m)

Spread

1-2 ft (0.3-0.6 m)

Flowers

Late spring to early summer; white tubular flowers, sometimes faintly flushed pink, with fine purple markings inside.

Foliage

Opposite, lance-shaped green stem leaves above a basal rosette. Some selections have burgundy foliage; basal leaves may persist through mild winters.

Growth

Moderate; usually forms a flowering clump within one or two growing seasons.

Care needed

Low

• Water during dry spells in the first growing season, allowing the surface soil to dry slightly between waterings.
• Avoid heavy feeding; add a light dressing of compost in spring only if growth is weak.
• Keep mulch clear of the crown and avoid sites with prolonged standing water.
• Support stems early with discreet twiggy stakes if they lean in partial shade or rich soil.
• Divide crowded clumps in spring when the centre weakens or flowering declines.

Pruning. Remove spent flower stems after flowering if you want to limit seedlings, or leave them for seed and winter structure. Cut old stems back to the basal foliage in late winter or early spring before new shoots lengthen.

Late winter

Cut down last year's stems, taking care not to damage the basal rosette.

Spring

Plant or divide clumps and water them in thoroughly.

Late spring

Add discreet supports where stems are leaning; water if the soil becomes dry during bud formation.

Summer

Remove spent flower stems to reduce self-seeding, or retain a few for seed.

Autumn

Collect ripe seed and remove unwanted seedlings while they are small.

Winter

Check that fallen leaves or heavy mulch are not smothering the crown.

• Plant repeated groups through a sunny mixed border for upright white flowers between lower, rounded plants.
• Combine with prairie grasses, coneflowers and black-eyed Susans for a meadow-style succession of flowers.
• Use in white or moon gardens, where the pale flowers stand out against dark foliage.
• Place near paths or seating to watch bumblebees visiting the flowers.

Garden styles it suits: Cottage garden, Native meadow, New perennial (prairie), Pollinator garden, White garden and Midwest prairie.

Plant it with: Purple coneflower, Black-eyed Susan, Little bluestem, Prairie dropseed, Wild bergamot and Threadleaf coreopsis.

Wildlife: The flowers provide nectar and pollen for bees, especially bumblebees. Retained stems provide overwintering habitat for insects; avoid clearing every stem in autumn.

• Crown or root rot in persistently waterlogged soil: improve drainage or move the plant to a better-drained position.
• Powdery mildew in crowded planting: increase spacing, maintain steady soil moisture and remove badly affected foliage.
• Slugs or snails damaging young shoots: inspect new growth and use barriers, hand-picking or locally approved iron-phosphate bait.
• Flopping stems in shade or overfed soil: provide more sun, stop nitrogen-rich feeding and support stems before they fall.

Not known to be toxic to cats, dogs, horses or people. No part is recognised as poisonous, but species-specific safety information is limited; do not treat the leaves, flowers or seeds as food.

• Common foxglove (Digitalis purpurea)

  Common foxglove has alternate, softly hairy leaves and much larger hanging bells, usually arranged along one side of a tall spike. Foxglove beardtongue has opposite stem leaves and smaller flowers in branching clusters.

• Hairy beardtongue (Penstemon hirsutus)

  Hairy beardtongue is usually shorter, with conspicuously hairy stems and narrower lavender-purple flowers tipped with white. Foxglove beardtongue has mostly smooth stems and broader, predominantly white flowers.

Penstemon refers to the flower's five stamens, including one sterile stamen, while digitalis means finger-like and refers to the foxglove-like tubular flowers.

Propagation. Divide established clumps in spring, or sow seed outdoors in autumn for natural winter chilling. Spring-sown seed may benefit from a cold, moist treatment. Seedlings from named cultivars may not retain the parent's foliage colour or other features.

Accepted botanical name

Penstemon digitalis

Native range

Alabama, Arkansas, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Michigan, Minnesota, Mississippi and Missouri.

Measured

Soil pH 5.5 to 7. Average height 68 cm.

Sources: GBIF (CC BY 4.0) and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.