Agrostemma (Corn Cockle) in Zone 9a & 9b
Agrostemma githago
When to plant agrostemma (corn cockle) 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. Agrostemma (Corn Cockle) tolerates either.
| Start indoors | Jan 18–Jan 25 |
|---|---|
| Direct sow / transplant outside | Feb 1–Feb 8 |
| Estimated bloom | Apr 17–Apr 24 (~75 days after planting) |
Spacing: 2 per square foot (square-foot-gardening spacing). Mature height: 2-3 ft.

Agrostemma, better known as corn cockle, has a history as an unwanted weed in European grain fields before it found a second life as a deliberately grown cut flower. Its delicate, magenta-pink blooms on tall, wiry stems have the airy, cottage-garden look that's hard to get from a sturdier, more structured flower.
How agrostemma (corn cockle) fits zone 9's season
Zone 9b's frost-free window runs about 293 days, from February 15 to December 5. Agrostemma (Corn Cockle) needs about 75 days from sowing to first harvest.
Good companions
No standout companions recorded yet for Agrostemma (Corn Cockle).
Where to buy agrostemma seeds
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See it growing
Search YouTube for "growing agrostemma (corn cockle)" 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 Agrostemma (Corn Cockle) in USDA zone 9b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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