Large-flowered beardtongue

Sun

Full sun.

Water

Low once established. Water new plants during dry spells, then water established plants only during prolonged drought.

Soil

Dry to moderately moist, sharply drained sandy, gravelly or rocky soil. Tolerates poor soil; avoid heavy, wet clay and rich, heavily amended beds.

Height

2-4 ft (0.6-1.2 m)

Spread

1-2 ft (0.3-0.6 m)

Flowers

Late spring to early summer; large tubular flowers in pale lavender, lilac-pink or occasionally white.

Foliage

Thick, smooth, blue-green leaves in opposite pairs; upper leaves have broad bases that clasp the stems. Basal leaves may persist through mild winters.

Growth

Moderate; seed-grown plants commonly flower in their second year.

Care needed

Low

• Pollinators
• Drought tolerant
• Cold hardy
• Heat tolerant
• Low allergen

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Very tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   1 ft (0.3 m)

2. After 1 year

   1.6 ft (0.5 m)

3. After 2 years

   2.3 ft (0.7 m)

4. After 3 years

   3 ft (0.9 m)

   full size

About 3 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Native to

the US

Growth rate

Moderate

• Plant with the crown at soil level in an open, sunny position.
• Water at the base during establishment, allowing the soil to dry between waterings.
• Avoid routine feeding and rich compost; excessive fertility encourages weak growth.
• Use a light gravel mulch rather than moisture-holding mulch against the crown.
• Allow some seed to ripen to replace short-lived plants; transplant seedlings while small.

Pruning. After flowering, remove spent flower stems unless you want seed. In early spring, cut dead stems back to the basal foliage without cutting into the crown.

Early spring

Remove dead stems and check that winter moisture has not collected around the crown.

Spring

Plant young plants after the soil becomes workable; water them through their first dry spells.

Late spring

Check new shoots for aphids and wash small colonies off with water.

Early summer

Remove faded flower stems, leaving a few if you want seed.

Late summer

Collect seed when capsules turn brown and begin to split.

Autumn

Sow seed outdoors in a protected pot or prepared seedbed for natural winter chilling.

• Plant small groups in a gravel garden, where the blue-green leaves contrast with stone.
• Combine with short prairie grasses and drought-tolerant flowers in an open prairie-style border.
• Use lavender flower spikes among yellow coreopsis or blanket flowers for an early-summer contrast.
• Place near the front or middle of a sunny wildlife border where visiting bees are easy to watch.

Garden styles it suits: Midwest prairie, Native meadow, Dry gravel garden, Desert / xeriscape, Pollinator garden and New perennial (prairie).

Plant it with: Little bluestem, Prairie dropseed, Butterfly weed, Lanceleaf coreopsis, Purple prairie clover and Blanket flower.

Wildlife: Flowers attract bumblebees and other native bees; hummingbirds may also visit in North America.

• Crown or root rot in wet soil: improve drainage or move plants to a raised, gravelly position; discard badly rotted plants.
• Short lifespan: let a few stems set seed and keep young replacement plants.
• Weak or flopping stems in shade or rich soil: provide full sun and stop feeding; move plants if necessary.
• Aphids on young shoots: wash them off with water and avoid broad-spectrum insecticides.

Not known to be toxic to people, cats, dogs or horses. Species-specific safety information is limited, so do not treat any part as edible.

• Foxglove beardtongue (Penstemon digitalis)

  Usually has smaller white flowers and greener, narrower leaves rather than the broad, blue-grey, stem-clasping leaves of large-flowered beardtongue.

• Cobaea beardtongue (Penstemon cobaea)

  Also has large pale purple flowers, but its leaves are generally hairy and toothed, unlike the smooth, un-toothed leaves of large-flowered beardtongue.

Grandiflorus means 'large-flowered', while beardtongue refers to the hairy sterile stamen inside the flower.

Propagation. Grow from seed sown outdoors in autumn, or give spring-sown seed a cold, moist treatment before sowing; germination can be uneven. Move seedlings while small, as established plants have deep roots and resent disturbance.

Accepted botanical name

Penstemon grandiflorus

In the US and Canada

Native in the lower 48 states.

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