Growing Penstemon (Beardtongue): A Complete Profile
By Growing Home Greens Team · August 20, 2026
Penstemon digitalis is a tough North American native that flowers in early summer and asks for very little.
Sow it before the frost date, not after
The seed germinates far better after a period of cold and damp. Our calendar puts it in about four weeks before the last frost for that reason, which is unusual among the flowers here. Sowing it in warm soil in May gives poor and erratic germination.
Seed needs light, so surface sow rather than covering.
Sizes and conditions
Two to four feet tall and about a foot and a half to two feet across, so it belongs on the north edge. Hardy zones 3 through 8, in full sun to partial shade. It flowers May to July.
Worth having next to vegetables
The tubular flowers are worked heavily by long-tongued bees and by hummingbirds. Planted at the end of a vegetable bed it pulls pollinators into the space at exactly the point in the season when squash and beans need them.
It tolerates poor dry soil and dislikes winter wet, which is the usual way to lose one.
Source: NC State Extension Gardener Plant Toolbox, Penstemon digitalis.
Companion planting guide for Penstemon (Beardtongue) · Find your planting dates
Typically viable in USDA zones 3-8. Not sure your zone? Look it up by ZIP code.
Method: Direct sow: Direct-sow outside. Penstemon (Beardtongue) doesn't transplant well, or doesn't need the extra time indoors.
See exact start-indoors, direct-sow, and harvest dates for your zone →
How many Penstemon (Beardtongue) plants fit per square foot?
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 2-4 ft.
Where to buy penstemon seeds
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See it growing
Search YouTube for "growing penstemon (beardtongue)" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
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Growing Penstemon (Beardtongue): A native perennial whose seed germinates better after a cold spell, so it goes in early.
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