Dusky Penstemon (Penstemon whippleanus), or Dusky Beardtongue, is a striking and unusual member of the penstemon genus, native to the Rocky Mountains and Intermountain West. This perennial wildflower is easily recognized by its dusky-hued, tubular flowers that range in color from deep maroon to purplish-brown, sometimes even greenish or nearly black—making it a rare visual contrast among native flora. It typically grows in cool, moist habitats, including subalpine meadows, montane forests, and shaded talus slopes.
Dusky Penstemon serves as a late-spring to summer nectar source for native bumblebees, solitary bees, and hummingbirds, which are especially drawn to its deep, bell-shaped flowers. Its darker bloom coloration is believed to attract specific bee species and possibly nocturnal pollinators as well. This penstemon contributes to native plant diversity in alpine and montane ecosystems and pairs well in the garden with other wildflowers such as Lupinus, Aquilegia, and Erigeron.
Dusky Penstemon prefers partial shade to full sun in cooler climates and thrives in moist but well-drained soils—especially loamy, silty, or lightly rocky substrates. More moisture-tolerant than many lowland penstemons, it does not tolerate hot, dry conditions without supplemental water. Seeds require cold stratification to germinate successfully, making fall sowing the best choice for natural conditions. Once established, it is a reliable, long-lived addition to native specimen gardens and high-elevation restoration sites.
Dusky Penstemon - Penstemon whippleanus
Scientific Name Penstemon whippleanus Habitat Subalpine meadows, montane forests, talus slopes USDA Zone 3 – 7 Native Region Rocky Mountains, Intermountain West Phenology Perennial Height 12 – 36" Light Requirement Partial Shade to Full Sun Water Requirement Moderate Soil Type Loamy, Silty, or Rocky Germination Time 21–45 days with cold stratification Difficulty ⸙⸙ Planting Season Fall or Early Spring Bloom Season Early to Mid-Summer Pollinators Bumblebees, Solitary Bees, Hummingbirds