Cold hardiness

Future

2050

2100

These values are location-based: this location's current hardiness is the baseline, and the 2050 value is a projected future climate for this same location.

Now

Zone 6b

USDA

Published baseline for this location from 1991-2020.

Source: USDA Plant Hardiness Zone Map 2023 (1991-2020 climatology) via ArcGIS FeatureServer

Well-suited

2050

Zone 7a

Plotwright

Projected zone for this same location in 2050 (2041-2070) using SSP3-7.0 (regional rivalry).

Well-suited

In plain terms: This location is in Zone 6b today. Its hardiness profile is cold winters, and coldest nights are typically around -3°F. By 2050, the projected hardiness zone is Zone 7a based on SSP3-7.0 (regional rivalry). That is a +0.5-zone shift from Zone 6b to Zone 7a by 2050.

✓

Well-suited today and still thriving in 2050.

Heat tolerance

Future

2050

2100

Heat tolerance values are location-based too: heat days today are observed at this site, and the 2050 value projects this same location under a future climate.

Loading AHS heat-zone data for this location...

Where this plant fits

Suitable across 40 ecoregions — 35 climate-resilient through 2070 · 5 suited today. Best matches first.

Appalachian mixed mesophytic forests

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Appalachian-Blue Ridge forests

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Arizona Mountains forests

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Blue Mountains forests

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Canadian Aspen forests and parklands

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Central Pacific Northwest coastal forests

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Central Tallgrass prairie

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Central-Southern Cascades Forests

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Colorado Rockies forests

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Cross-Timbers savanna-woodland

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What it needs

Conditions

Light

Full sun / Part shade

Water

Moderate water

Spacing

18"

Habit

Clumping erect perennial with basal foliage and tall vertical flowering stems

Care tips

•

Site in full sun + lean well-drained soil for the canonical upright habit — over-fertilized or shaded plantings produce floppy stems.

•

Plant 'Husker Red' for foliage-color design — burgundy-red leaves provide a year-round color contrast that the species form lacks.

•

Cut spent flower stems back to the basal foliage in late summer if self-sowing is unwanted; otherwise leave standing through fall for goldfinch + songbird seed forage.

Lifecycle

Planting

Plant in spring or fall in well-drained moist-to-dry loamy soil; NC State notes tolerance of clay if well-drained. Full sun produces the most flowers + sturdiest stems; light shade is tolerated. Among the most adaptable native perennials for residential landscapes.

Transplanting

Transplant when dormant or in early spring before significant new growth. Mature clumps with developed root systems move successfully with adequate root mass preservation.

Early growth

Water through the first season; once established the species is drought-tolerant per NC State. Cut back stems after flowering if seed self-sowing is unwanted; otherwise leave standing for goldfinch + small-songbird seed forage.

Maturity

Mature plants reach 2-5 feet tall with 18-24 inch spread. Long-lived; clumps expand gradually over years without aggressive spreading. Stems may flop in partial shade or over-fertilized sites; full sun + lean soil produces the canonical upright habit.

Propagation

Easily propagated by seed (cold stratification recommended), division of established clumps in spring or fall, or by softwood cuttings in early summer. 'Husker Red' and other named cultivars are propagated by division to maintain the foliage-color trait (seed-grown plants vary in foliage color intensity).

Pollination

Self-fertile

Perfect tubular flowers produce viable seed without a partner. NC State documents specialized native bee visitation — Osmia (Melanosmia) distincta, the Penstemon mason bee, is a documented specialist pollinator. The tubular flower architecture suits long-tongued bees, hummingbirds, and butterflies; short-tongued bees may rob nectar by slitting the corolla side rather than entering legitimately.

Plants don't grow alone

Larval host

Butterfly

Common buckeye (Junonia coenia)

Penstemon (Plantaginaceae, iridoid-bearing) is a documented common-buckeye larval-host genus (Calscape); P. digitalis is not species-cited, so genus-level inference.

Pollinates

Bee

Common eastern bumblebee (Bombus impatiens)

Long-tongued bumblebees access the tubular corolla efficiently and serve as primary pollinators alongside the specialist Penstemon mason bee (Osmia distincta).

Nectar forage

Bird

Ruby-throated hummingbird (Archilochus colubris)

NC State explicitly names hummingbirds among visitors; the long white tubular flowers suit the hummingbird hover-feed approach.

Nectar forage

Butterfly

Eastern tiger swallowtail (Papilio glaucus)

Nectar forage

Bee

European honeybee (Apis mellifera)

For people

Not eaten by humans

Foxglove beardtongue is grown as an ornamental and pollinator plant, not as food. NC State explicitly clarifies: "Despite the specific epithet, this plant is not foxglove (Digitalis spp.) and lacks the toxicity associated with foxglove." The flower-shape resemblance is convergent, not phylogenetic — Penstemon (family Plantaginaceae) is unrelated to Digitalis (Plantaginaceae but different clade) and does NOT share the cardiac-glycoside profile.

Native range

Native across 35 US states + 4 CA provinces.

AHS heat range

1-11

Native ecoregions

Naturally belongs in 21 ecoregions — its native range crosses a state or province each one spans (not necessarily this exact habitat).

Appalachian mixed mesophytic forests

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Appalachian-Blue Ridge forests

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Atlantic coastal pine barrens

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Central Tallgrass prairie

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Chihuahuan desert

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Cross-Timbers savanna-woodland

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Eastern Canadian Forest-Boreal transition

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Eastern Great Lakes lowland forests

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Edwards Plateau savanna

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Flint Hills tallgrass prairie

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Climate notes

•

NC State Extension lists Penstemon digitalis for USDA hardiness zones 3a-8b across central and eastern USA (34 states from the Midwest through the Southeast).

•

Drought-tolerant once established per NC State; tolerates clay + well-drained sandy soils alike. Among the most adaptable native perennials for the residential landscape.

•

NC State: "It has no serious disease or pest problems." Among the most maintenance-free native perennials available — a load-bearing meadow + border species.

In the designer

Growth over time

24-48" tall · 18-24" spread

Mature clump; very drought-tolerant once established.

Design roles: Pollinator · Border · Focal point

Seasonal interest

Spring

Summer

Fall

Winter

Filled = the plant has seasonal interest · ▾ now = your current season

Foxglove beardtongue

At a glance

Related products

Why it matters

Cold hardiness

Heat tolerance

Where this plant fits

What it needs

Lifecycle

Pollination

Plants don't grow alone

For people

Native range

Climate notes

In the designer

Seasonal interest

Sources & citations