Bachelor's Button (Cornflower) in Zone 5a & 5b
Centaurea cyanus
Yes, bachelor's button (cornflower) grows in zones 5a and 5b. Start seeds indoors Mar 22–Mar 29 and plant out Apr 26–May 3.
When to plant bachelor's button (cornflower) in zone 5b
Zones 5a and 5b share the same average frost dates, so this page covers both.
Method: Either: Start indoors for an earlier harvest, or direct-sow outside for less fuss. Either works.
| Start indoors | Mar 22–Mar 29 |
|---|---|
| Direct sow / transplant outside | Apr 26–May 3 |
| Estimated bloom | Jul 10–Jul 17 (~75 days after planting) |
Spacing: 3 per square foot (square-foot-gardening spacing). Mature height: 1-3 ft.
Plant alongside it in zone 5b
These go outside within two weeks of bachelor's button (cornflower) in zone 5b, so one planting day can cover them.
- Agrostemma (Corn Cockle)Apr 26–May 3
- AstilbeApr 26–May 3
- Basket-of-GoldApr 26–May 3
- Bupleurum (Thoroughwax)Apr 26–May 3
- CalendulaApr 26–May 3
- California PoppyApr 26–May 3
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 5's season
Zone 5b's frost-free window runs about 148 days, from May 10 to October 5. Bachelor's button (cornflower) needs about 75 days from sowing to first bloom.
Bachelor's Button (Cornflower) planting windows in every zone
Zone 5b is highlighted. Useful for comparing against a neighbouring zone, or for a garden somewhere else.
| Zone | Start indoors | Sow or plant out | Bloom |
|---|---|---|---|
| 2a & 2b | Apr 1–Apr 8 | May 6–May 13 | Jul 20–Jul 27 |
| 3a & 3b | Apr 11–Apr 18 | May 16–May 23 | Jul 30–Aug 6 |
| 4a & 4b | Mar 27–Apr 3 | May 1–May 8 | Jul 15–Jul 22 |
| 5a & 5b (your zone) | Mar 22–Mar 29 | Apr 26–May 3 | Jul 10–Jul 17 |
| 6a & 6b | Mar 7–Mar 14 | Apr 11–Apr 18 | Jun 25–Jul 2 |
| 7a & 7b | Feb 20–Feb 27 | Mar 27–Apr 3 | Jun 10–Jun 17 |
| 8a & 8b | Feb 4–Feb 11 | Mar 11–Mar 18 | May 25–Jun 1 |
| 9a & 9b | Dec 28–Jan 4 | Feb 1–Feb 8 | Apr 17–Apr 24 |
| 10a & 10bFall window | Not usually | Sep–Nov | ~75 days after planting |
| 11a & 11b | Nov 13–Nov 20 | Dec 18–Dec 25 | Mar 3–Mar 10 |
Bloom dates are about 75 days after the sow or plant-out date, not after starting seeds indoors.
Zone 2 sows before zone 3 here, which looks wrong and is not. USDA zones rank winter cold, not season length, and zone 2 is mostly interior Alaska, where hard winters come with warm summers. More on what a zone measures.
Good companions
No well-established companions for bachelor's button (cornflower).
Where to buy bachelor's button seeds
Botanical Interests · True Leaf Market · High Mowing Organic Seeds (each supplier's bachelor's button seeds)
See why we recommend these suppliers →
As an Amazon Associate we earn from qualifying purchases. Some links on this page also go to other retailers we may earn a commission from as an affiliate, at no extra cost to you. We only recommend products with a clear consensus of positive, independent reviews, or ones we bought and use ourselves. Each item on our gear page says which.
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 5b calendar · Plan your beds in the Garden Designer →
%20in%20USDA%20zone%205b%3A%20when%20to%20start%20seeds%20indoors%2C%20when%20to%20direct-sow%2C%20and%20when%20to%20expect%20a%20bloom.)
Pin this for later
Growing Bachelor's Button (Cornflower) in USDA zone 5b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
Save to Pinterest