Penstemon (Beardtongue) in Zone 6a & 6b
Penstemon digitalis
Yes, penstemon (beardtongue) grows in zones 6a and 6b and comes back each year. Plant it outside Mar 28–Apr 4.
When to plant penstemon (beardtongue) in zone 6b
Zones 6a and 6b share the same average frost dates, so this page covers both.
Method: Direct sow: Direct-sow outside. It doesn't transplant well, or doesn't need the extra time indoors.
| Start indoors | Not typically started indoors |
|---|---|
| Direct sow / transplant outside | Mar 28–Apr 4 |
| Estimated bloom | First real harvest the season after planting |
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 2-4 ft.
Before you plant: Penstemon (beardtongue) has a winter-hardiness note for zone 6b. See the details below.
Plant alongside it in zone 6b
These go outside within two weeks of penstemon (beardtongue) in zone 6b, so one planting day can cover them.
- Bleeding HeartMar 28–Apr 4
- LarkspurMar 28–Apr 4
- Black-Eyed SusanApr 4–Apr 11
- Clarkia (Farewell-to-Spring)Apr 4–Apr 11
- Cynoglossum (Chinese Forget-Me-Not)Apr 4–Apr 11
- Phacelia (Lacy Phacelia)Apr 4–Apr 11

Penstemon digitalis is a tough North American native that flowers in early summer and asks for very little.
How penstemon (beardtongue) fits zone 6's season
Zone 6b's frost-free window runs about 173 days, from April 25 to October 15. Penstemon (beardtongue) takes about 1 growing season to reach full flowering, so what matters here is how many of these seasons it gets, not whether one is long enough.
Penstemon (beardtongue) is hardy in zones 3-8, so in zone 6b it stays in the ground through winter and comes back rather than being replanted. Allow about 1.75 ft of spread at maturity.
Penstemon (Beardtongue) planting windows in every zone
Zone 6b is highlighted. Useful for comparing against a neighbouring zone, or for a garden somewhere else.
| 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 (your zone) | 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 |
Good companions
No well-established companions for penstemon (beardtongue).
Where to buy penstemon seeds
Botanical Interests · True Leaf Market (each supplier's penstemon seeds)
See why we recommend these suppliers →
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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)
← Back to the full zone 6b calendar · Plan your beds in the Garden Designer →

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Growing Penstemon (Beardtongue) in USDA zone 6b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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