penstemon (digitalis) (Penstemon digitalis), photographi

How to Grow Penstemon Digitalis

Penstemon digitalis · Zones 4-10

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, part sun, pH 5.5–7.

USDA zones
4–10
Not verified
Soil pH
5.5–7
USDA PLANTS
Sun
Part Sun
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.

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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 part sun — at least 4 hours of direct sun a day — and soil from pH 5.5 to 7, on fast-draining ground.

USDA Zones

4-10

Not verified

Soil pH

5.5 - 7

USDA PLANTS

Sun

Part Sun

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

  1. Start the season right

    Plant penstemon digitalis in part sun with at least 4 hours of direct sun, once the soil has warmed and frost risk has passed.

  2. 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.

  3. Water while it roots in

    Water deeply while penstemon digitalis establishes, letting the soil dry between soakings; once its roots are in, it rides out dry spells on its own.

  4. 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 highlighted on the USDA national hardiness zone map

Zones 4–10·Where Penstemon Digitalis growsOpen map →

This map is derived from the USDA ARS / PRISM Plant Hardiness Zone Map (2023) and is not the official USDA Plant Hardiness Zone 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

The line runs through

13 states

3 of 13 shown

Penstemon Digitalis’s band covers part of each of these states — which side of the line your county sits on changes the answer, and each state page draws it.

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.

Good to know

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.

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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:

Your soil pHYour frost-free daysYour sun & shade

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•ASPCA

Frequently asked questions

Can I grow Penstemon Digitalis in my zone?

Penstemon Digitalis grows in USDA hardiness zones 4 through 10. 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. 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 does well in partial sun — around 4 hours of direct sun, and it takes some afternoon shade in stride. That flexibility makes it a good match for a bed the house or a nearby tree shades for part of the day. A Growable Ground report maps how the sun actually falls on your land, hour by hour, so you can set it where the light lines up.

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.)