Rue in Zone 4a & 4b
Ruta graveolens
Yes, rue grows in zones 4a and 4b. Start seeds indoors Mar 27–Apr 3 and plant out May 22–May 29.
When to plant rue in zone 4b
Zones 4a and 4b share the same average frost dates, so this page covers both.
Method: Start indoors: Start indoors from seed, then transplant outside. It needs a head start most zones can't give it by direct-sowing alone.
| Start indoors | Mar 27–Apr 3 |
|---|---|
| Direct sow / transplant outside | May 22–May 29 |
| Estimated harvest | Aug 20–Aug 27 (~90 days after transplanting) |
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 2-3 ft.
Plant alongside it in zone 4b
These go outside within two weeks of rue in zone 4b, so one planting day can cover them.
- BasilMay 29–Jun 5
- BorageMay 15–May 22
- RosemaryMay 29–Jun 5
- DillMay 8–May 15
- CatmintMay 22–May 29
- Citronella Plant (Mosquito Plant)May 22–May 29
Rue is a blue-gray, woody-based perennial with a long history as a medicinal herb, though it's grown today mostly for its striking foliage color and as a larval host for swallowtail butterflies rather than for the kitchen. The leaves are toxic in any real quantity and can irritate skin in sunlight, so it's a plant to handle with gloves, not eat.
How rue fits zone 4's season
Zone 4b's frost-free window runs about 128 days, from May 15 to September 20. Rue needs about 90 days from transplant to first harvest.
Rue planting windows in every zone
Zone 4b is highlighted. Useful for comparing against a neighbouring zone, or for a garden somewhere else.
| Zone | Start indoors | Sow or plant out | Harvest |
|---|---|---|---|
| 4a & 4b (your zone) | Mar 27–Apr 3 | May 22–May 29 | Aug 20–Aug 27 |
| 5a & 5b | Mar 22–Mar 29 | May 17–May 24 | Aug 15–Aug 22 |
| 6a & 6b | Mar 7–Mar 14 | May 2–May 9 | Jul 31–Aug 7 |
| 7a & 7b | Feb 20–Feb 27 | Apr 17–Apr 24 | Jul 16–Jul 23 |
| 8a & 8b | Feb 4–Feb 11 | Apr 1–Apr 8 | Jun 30–Jul 7 |
| 9a & 9b | Dec 28–Jan 4 | Feb 22–Mar 1 | May 23–May 30 |
Harvest dates are about 90 days after the sow or plant-out date, not after starting seeds indoors.
Good companions
No well-established companions for rue.
Where to buy rue seeds
True Leaf Market (each supplier's rue seeds)
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See it growing
Search YouTube for "growing rue" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 4b calendar · Plan your beds in the Garden Designer →
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Growing Rue in USDA zone 4b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.
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