Bachelor's Button (Cornflower) in Zone 9a & 9b
Centaurea cyanus
When to plant bachelor's button (cornflower) in zone 9b
Zones 9a and 9b share the same average frost dates in our data, so this page covers both.
Method: Either: Start indoors for an earlier harvest, or direct-sow outside for less fuss. Bachelor's Button (Cornflower) tolerates either.
| Start indoors | Dec 28–Jan 4 '27 |
|---|---|
| Direct sow / transplant outside | Feb 1–Feb 8 |
| Estimated bloom | Apr 17–Apr 24 (~75 days after planting) |
Spacing: 3 per square foot (square-foot-gardening spacing). Mature height: 1-3 ft.

Bachelor's button (also sold as cornflower) is about as low-effort as annual flowers get. It tolerates cold better than most, fills in fast, and doesn't ask for much once it's in the ground. Wiry 1- to 3-foot stems carry small, fringed, frilly round blooms, most often blue, though pink, white, and maroon show up in mixes too.
How bachelor's button (cornflower) fits zone 9's season
Zone 9b's frost-free window runs about 293 days, from February 15 to December 5. Bachelor's Button (Cornflower) needs about 75 days from sowing to first harvest.
Good companions
No standout companions recorded yet for Bachelor's Button (Cornflower).
Where to buy bachelor's button seeds
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing bachelor's button (cornflower)" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 9b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →

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Growing Bachelor's Button (Cornflower) in USDA zone 9b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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