China Aster in Zone 5a & 5b
Callistephus chinensis
When to plant china aster in zone 5b
Zones 5a and 5b share the same average frost dates in our data, so this page covers both.
Method: Start indoors: Start indoors from seed, then transplant outside. China Aster needs a head start most zones can't give it by direct-sowing alone.
| Start indoors | Mar 22–Mar 29 |
|---|---|
| Direct sow / transplant outside | May 17–May 24 |
| Estimated bloom | Aug 15–Aug 22 (~90 days after transplanting) |
Spacing: 4 per square foot (square-foot-gardening spacing). Mature height: 1.5-2.5 ft.
China aster is not related to the perennial garden asters despite the common name; it's a true annual grown from seed each year for its full, peony-like cut-flower blooms.
How china aster fits zone 5's season
Zone 5b's frost-free window runs about 148 days, from May 10 to October 5. China Aster needs about 90 days from transplant to first harvest.
Good companions
No standout companions recorded yet for China Aster.
Where to buy china aster seeds
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing china aster" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 5b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →
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Growing China Aster in USDA zone 5b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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