Blue Penstemon
Rocky Mountain Blue Penstemon (Penstemon strictus) is a striking native wildflower that brings cool blue spires of tubular blooms to any sunny garden. Hardy from zones 4 through 9, this upright perennial grows 24 to 36 inches tall and thrives in lean, well-drained soil with minimal water once established. Its frost-hardy nature and ability to flourish in full sun to partial shade make it a reliable performer in mountain gardens, prairie settings, and anywhere you want a low-maintenance native that attracts pollinators without fussing.
Partial Sun
Low
4-9
36in H x ?in W
Perennial
Moderate
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Deep blue flowers clustered along vertical spikes create a striking architectural presence in the garden. This native penstemon is remarkably drought-tolerant once rooted, asking for little water and no fertilizer, which means it settles into gardens and returns stronger each year. The cool germination requirement near 55°F means you can start seeds indoors in late winter or sow them directly in fall, giving you flexibility in how you propagate this tough, beautiful perennial.
Rocky Mountain Blue Penstemon is grown primarily as an ornamental flowering plant for perennial borders, rock gardens, and pollinator gardens. Its vertical flower spikes add height and structure to mixed plantings, and the nectar-rich blooms draw bees, hummingbirds, and other beneficial insects throughout its flowering season.
Start seeds indoors 6 to 8 weeks before your average last frost date. Sow seeds at a depth of 1/8 inch in a seed-starting mix, keeping soil temperature near 55°F for best germination. Penstemon seeds germinate more reliably in cooler soils, so avoid warm heat mats.
Transplant seedlings outdoors 6 to 8 weeks before your average last frost date, once they've developed true leaves and reached about 2 inches tall. Harden off seedlings gradually over a week before planting in their final location. Space plants 18 inches apart in well-drained soil.
Sow seeds directly outdoors 6 to 8 weeks before your average last frost date, or scatter seeds in late fall for natural cold stratification. Press seeds lightly into the soil surface and keep the seeding area consistently moist until germination.
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