Wildflower Archive

woodland wildflower

Lilac Penstemon

Penstemon gracilis

Also known as Lilac Beardtongue, Slender Penstemon, Slender Beardtongue

Lilac Penstemon (Penstemon gracilis)1 of 2
Sydenham Edwards & John Lindley

Native to the Rockies, the Great Plains, and the Midwest and southern Canada

Southwestern Ontario to northeastern British Columbia, south to Wisconsin, northwestern Iowa, southern Nebraska and along the eastern slope of Rockies from Montana to New Mexico

  • Light Partial shade Sun tolerance
  • Moisture Moist Moisture preference
  • Zones 2–7 Cold to heat range
  • Bloom Jun–Jul Flowering time
  • Height up to 2 ft to 0.6 m
  • Life cycle Perennial Annual to perennial
Full details, see below

In the garden

A woodland wildflower for partial shade and evenly moist soil. Its purple flowers peak in June. At up to 2 ft, it suits shade gardens and woodland edges. Hardy in USDA zones 2–7.

Growing conditions

Light
Full sun Partial shade Full shade
Moisture
Dry Moist Wet

Hardiness zones

Find your zone:

When it blooms

The Lilac Penstemon's purple flowers bloom June to July, peaking in June. This early-summer display draws bees and flower flies.

Jun–JulJanFebMarAprMayJunJulAugSepOctNovDec

Lilac Penstemon blooms purpleFoliage

Pollinators & wildlife

  • Bees Black-tailed Bumble Bee
    also Red-belted Bumble Bee, Hunt's Bumble Bee, Two-form Bumble Bee +22 more Great Basin Bumble Bee, Orange-tipped Wood-digger, White-shouldered Bumble Bee, Western Bumble Bee, Morrison's Bumble Bee, Black-and-gray Leafcutter Bee, Bumblebee-like Digger Bee, White-fronted Small-Mason, Annulate Masked Bee, Anthophora ursina, Kincaid's Cellophane Bee, Osmia proxima, Osmia bruneri, Osmia tristella, Osmia densa, Osmia nanula, Heriades gracilior, Osmia pentstemonis, Washington Miner Bee, Cinquefoil Masked Bee, Ashmeadiella pronitens, Melecta fulgida
  • Flower flies Margined Calligrapher also Long-tailed Aphideater, Black-margined Flower Fly, grasshopper bee fly
  • Wasps Euodynerus foraminatus also Pseudomasaris vespoides
  • Also visited by
    • Hummingbirds: Broad-tailed Hummingbird
    • Butterflies: Papilio andronicus

Butterflies that use this plant

Documented host and nectar records. Each links to a planting guide for that butterfly.

Full plant details

Where it grows

Habitat
WoodlandThe wild plant community it grows in.
Native range
The Rockies, the Great Plains, and the Midwest and southern CanadaUnited States (11): CO, IA, MI, MN, MT, ND, NE, NM, SD, WI, WY. Canada (2): MB, SK. Where it grows wild on its own, by state and province.
Native distribution
Southwestern Ontario to northeastern British Columbia, south to Wisconsin, northwestern Iowa, southern Nebraska and along the eastern slope of Rockies from Montana to New MexicoThe same native range, usually more exact than the state list, and often noting where it has spread beyond it.

Growing conditions

Light
Partial shadeHow much sun it takes, from full sun to full shade.
Moisture
MoistThe soil dampness it prefers, from dry to wet.
Hardiness zones
USDA 2–7 · Canadian 2–5The cold-to-heat climate range it survives.
Soil
Sandy or gravelly soilsThe soils it grows in naturally.

Growth & form

Height
up to 2 ft (to 0.6 m)Typical mature height.
Life cycle
PerennialWhether it lives a single season (annual), two (biennial), or returns for years (perennial).

Flowers, foliage & fruit

Type
WildflowerWhat kind of plant it is.
Bloom
Jun–JulWhen it flowers.
Flower color
PurpleThe bloom color, or colors.
Fruit/Seeds
Capsule; ripens Jun–AugThe seed or fruit it sets after flowering.
Toxicity
None knownWhether any part is poisonous to people or pets.