Pennyroyal in Zone 6a & 6b
Mentha pulegium
Yes, pennyroyal grows in zones 6a and 6b and comes back each year. Plant it outside Apr 25–May 2.
When to plant pennyroyal 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 | Apr 25–May 2 |
| Estimated harvest | First real harvest the season after planting |
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 0.5-1 ft.
Before you plant: Pennyroyal 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 pennyroyal in zone 6b, so one planting day can cover them.
- BasilMay 9–May 16
- BorageApr 25–May 2
- DillApr 18–Apr 25
- RosemaryMay 9–May 16
- American GinsengApr 25–May 2
- AniseApr 25–May 2
Pennyroyal is a mint, it smells wonderful, and it is the one herb here that comes with a serious health warning.
How pennyroyal fits zone 6's season
Zone 6b's frost-free window runs about 173 days, from April 25 to October 15. Pennyroyal takes about 1 growing season to reach first worthwhile harvest, so what matters here is how many of these seasons it gets, not whether one is long enough.
Pennyroyal is hardy in zones 6-9, so in zone 6b it stays in the ground through winter and comes back rather than being replanted. Allow about 3 ft of spread at maturity.
Pennyroyal 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 | Harvest |
|---|---|---|---|
| 6a & 6b (your zone) | Not usually | Apr 25–May 2 | First real harvest the season after planting |
| 7a & 7b | Not usually | Apr 10–Apr 17 | First real harvest the season after planting |
| 8a & 8b | Not usually | Mar 25–Apr 1 | First real harvest the season after planting |
| 9a & 9b | Not usually | Feb 15–Feb 22 | First real harvest the season after planting |
Good companions
No well-established companions for pennyroyal.
Where to buy pennyroyal seeds
True Leaf Market (each supplier's pennyroyal seeds)
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing pennyroyal" 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 Pennyroyal in USDA zone 6b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.
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