Penstemon Digitalis is a perennial grown for its purple blooms, which open in late spring and return year after year. It's hardy across USDA zones 4 through 10, shrugs off dry spells and grows just as well in a container as in the ground. Its late spring flowers are a real draw for native bees, butterflies, and hummingbirds.
Penstemon Digitalis — the short answer
Penstemon Digitalis: grown in zones 4–10, shade, pH 5.5–7.
- USDA zones
- 4–10
- Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
- Soil pH
- 5.5–7
- USDA PLANTS
- Sun
- Shade
- Growable Ground Plant Database
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — each tile names its own row's source, because per-field provenance varies.
Score Penstemon Digitalis on your exact land.
Zone averages can't see the slope, soil, frost, and sun that decide whether penstemon digitalis actually takes — and those shift from one yard to the next. Enter your address and we'll score penstemon digitalis against your land's real conditions.
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What Penstemon Digitalis is
Penstemon Digitalis grows as a perennial and reaches around three feet at maturity. It blooms purple in late spring. It's also well suited to containers.
How to grow Penstemon Digitalis
Penstemon Digitalis grows in USDA zones 4 through 10. Penstemon Digitalis does best in shade — at least 2 hours of direct sun a day — and soil from pH 5.5 to 7, on fast-draining ground. It needs a growing season of at least 110 frost-free days, which is why climate matters as much as soil.
USDA Zones
4-10
USDA PHZM 2023
Soil pH
5.5 - 7
USDA PLANTS
Sun
Shade
Growable Ground plant catalog
Drainage
excessive (dry/moderately dry)
Growable Ground plant catalog
Cold Hardiness
-38°F
The coldest temperature this plant is documented to survive.
USDA PLANTS
Mature Height
3 ft
Growable Ground plant catalog
Frost-Free Days
110+
The frost-free stretch it needs start to finish — short-season areas may need an indoor head start.
Growable Ground plant catalog
Start the season right
Plant penstemon digitalis in shade with at least 2 hours of direct sun, once the soil has warmed and frost risk has passed.
Match the soil
Penstemon Digitalis prefers pH 5.5 to 7 (USDA PLANTS). A quick soil test from your local Extension lab tells you whether to add lime or sulfur to land in band.
Water steadily
Keep the root zone evenly moist through establishment. Match watering to the plant's drainage preference and your local rainfall.
Harvest at its peak
Cut penstemon digitalis blooms in the cool of the morning, just as they open, for the longest display.
Where Penstemon Digitalis thrives
Penstemon Digitalis is hardy across USDA zones 4 through 10. Zone is only the starting point, though: the soil pH, drainage, and frost dates on your specific land decide how well it actually does.
A USDA zone is a 10°F band of average annual extreme winter minimum, so zones 4–10 spans average winter lows from -30°F to 40°F (USDA PHZM 2023). Across the 50 states and DC, that band covers 38 outright and splits 13 more down the middle — and which side of that line your land sits on changes the answer.
Zones 4–10·Where Penstemon Digitalis growsOpen map →
Where Penstemon Digitalis stands, state by state
Penstemon Digitalis is rated for zones 4–10 — a cold floor USDA puts at -30 to -20°F. Across the 50 states and DC, 38 sit fully inside that band, the line runs through 13 more, and 0 sit outside it — and inside every split state, the same line runs on at county grain.
Fully inside zones 4–10
38 states
3 of 38 shown
State zone extents: USDA Plant Hardiness Zone Map (PHZM) 2023. A zone is a 10°F band of average annual extreme minimum temperature, so a state that splits the band contains the boundary — its own page draws the county line, and a parcel report resolves which side your land sits on.
What grows around Penstemon Digitalis
Growing guides for penstemon digitalis
In rotation planning, penstemon digitalis counts as a Other — beds recover best when other crops don’t follow each other in the same spot year over year. (Growable Ground derivation — crop-rotation group from botanical family)
Related plants in perennial flower
Good to know
Good news for pet owners — penstemon digitalis isn't known to be toxic to dogs or cats. (Source: ASPCA.)
Penstemon Digitalis is a standout pollinator plant — high value to bees and other pollinators. (Source: Xerces Society.)
Your land is one point inside Penstemon Digitalis's range
This page resolves to the species. Your state page draws the county line, and a report reads the parcel — the soil pH, drainage, sun, and frost dates on your exact ground, which no species average can see.
See if Penstemon Digitalis will thrive on your land
Zone averages are a start. Your exact soil pH, drainage, sun exposure, and frost dates shape whether penstemon digitalis actually takes — we score it against the real conditions at your address.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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How we know this about Penstemon Digitalis
The figures above are cited per row, not per site: the pH band names this plant’s own source column, the three temperature figures each carry their own, and days-to-maturity cites the publication that actually lists it. All of it comes from the Growable Ground Plant Database — a compilation over FAO ECOCROP, USDA PLANTS, and university Extension sources, published openly with per-field provenance.
Grounded inUSDA PLANTS Database•USDA PHZM•ASPCA
Frequently asked questions
Can I grow Penstemon Digitalis in my zone?
Penstemon Digitalis grows in USDA hardiness zones 4 through 10 (USDA PHZM 2023). Zone is one factor — soil pH, drainage, and frost dates on your specific parcel also shape whether it takes.
When should you plant Penstemon Digitalis?
Most growers plant penstemon digitalis after the last spring frost, once the soil has warmed, leaving enough of the season for its 110-day frost-free need. Your local frost dates set the exact window — a Growable Ground report reads them for your address.
How much sun does Penstemon Digitalis need?
Penstemon Digitalis is shade-tolerant — it gets by on as little as 2 hours of direct sun, so it earns a place most vegetables can't use. A north-facing strip or the ground under a leafy canopy is right where it belongs. A Growable Ground report shows which corners of your land stay shaded through the day, turning those dim spots into planting spots.
What soil does Penstemon Digitalis need?
Penstemon Digitalis prefers soil pH 5.5 to 7, on fast-draining ground (USDA PLANTS). Your report scores your parcel's actual soil against that using USDA SSURGO data.
Does Penstemon Digitalis attract pollinators?
Yes — penstemon digitalis's flowers are a strong nectar and pollen source for native bees, butterflies, and hummingbirds. (Source: Xerces Society.)
Is Penstemon Digitalis safe for pets?
Penstemon Digitalis is not known to be toxic to dogs or cats based on available data. Always supervise pets around new plantings. (Source: ASPCA.)