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.
Mature height: 2-4 ft
Method: Direct sow: Direct-sow outside. It doesn't transplant well, or doesn't need the extra time indoors.
When to plant penstemon (beardtongue), by zone
Every zone penstemon (beardtongue) grows in. Pick your zone in the header and it will be highlighted here. Each zone links to its full page.
| Zone | Start indoors | Sow or plant out | Bloom |
|---|---|---|---|
| 3a & 3b | Not usually | May 2–May 9 | First real harvest the season after planting |
| 4a & 4b | Not usually | Apr 17–Apr 24 | First real harvest the season after planting |
| 5a & 5b | Not usually | Apr 12–Apr 19 | First real harvest the season after planting |
| 6a & 6b | Not usually | Mar 28–Apr 4 | First real harvest the season after planting |
| 7a & 7b | Not usually | Mar 13–Mar 20 | First real harvest the season after planting |
| 8a & 8b | Not usually | Feb 25–Mar 4 | First real harvest the season after planting |
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.
Varieties worth considering
- Husker Red: The 1996 Perennial Plant of the Year: white flowers in July and August over bronze-red foliage, on plants about 30 inches tall. Purdue Extension notes it works in the garden and the vase and does well in full sun to light shade, as long as the soil drains. (source)
Why each variety is listed comes from the source shown next to it. We haven't grown these ourselves yet, so treat this as a research-backed starting point, not a personal endorsement. The buy links are separate from those sources: they go to seed suppliers that sell that exact variety, and we may earn a commission on some of them.
Where to buy penstemon seeds
Botanical Interests · True Leaf Market (each supplier's 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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