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Foxglove beardtongue
Habit (mature) · Cbaile19 / Wikimedia Commons · CC0
Limited coverage
Foxglove beardtongue
Penstemon digitalis
A native upright perennial of central + eastern North American prairies, woodland margins, and open woods producing tall vertical spires of white tubular flowers in late spring. The species name "digitalis" honors a flower-shape resemblance to true foxglove (Digitalis purpurea) — but Penstemon digitalis is NOT toxic in the same way (NC State explicit: "lacks the toxicity associated with foxglove"). Specialist Penstemon mason bee (Osmia distincta) relationship per NC State. The popular 'Husker Red' cultivar adds burgundy foliage for foliage-color design.
Native: 35 US states + 4 CA provinces
Review: Source-backed
Climate fit: broad (83/100)
Pollinator
Border
Focal point
Light
Full sun / Part shade
Water
Moderate water
Mature size
24-48" tall · 18" apart
Hardy in zones
3a-8b
brutally cold to frosty winters
Summer heat range
Cool-Hot
cool to hot summers Interim Plotwright tier until the plant AHS range is authored.
Native in Illinois
Yes
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A documented larval host for the Common buckeye — caterpillars feed on its foliage before becoming the next generation.
Wildlife relationships
Cold hardiness
Now
Zone 6b
USDA
Chicago, IL · 1991-2020 average annual coldest day
Source: USDA Plant Hardiness Zone Map 2023 (1991-2020 climatology) via ArcGIS FeatureServer
Well-suited
2050
Zone 7b
Plotwright
Your zone + climate-model shift · SSP3-7.0 (regional rivalry)
Well-suited
In plain terms: cold winters — coldest nights typically around -3°F.
Well-suited today and still thriving in 2050.
Heat tolerance
Loading current AHS heat-zone and plant heat-fit data at your coordinates…
Sources & citations
Cite this page
For lesson plans, articles, or research that uses this page. To cite a single upstream fact instead, use its specific source listed below.
Plotwright. (2026, May 17). Foxglove beardtongue (Penstemon digitalis). Retrieved 2026, June 5, from https://plotwright.garden/plants/foxglove-beardtongue
Sources for every fact
Every fact on this page traces to a source. 18 fields cited18 source-backed.
NC State Extension Gardener Plant Toolbox
University extension service
Backs 17 fields
Identity
Summary
Plant type
Light
Moisture
Hardiness
Heat zone
Size
Spacing
Habit
Design roles
Seasonal interest
Growth stages
Lifecycle
Regional guidance
Success tips
Designer notes
Wikimedia Commons
Photo · CC0
Backs 1 field
Image
Community photos
The photos above are our reviewed reference set, curated for accuracy.
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