Growing Bachelor's Button: A Complete Profile
By Growing Home Greens Team · July 18, 2026
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.
Sowing it
It can go in either way: start indoors about 7 weeks before your last frost, or direct-sow about 2 weeks before that date at a 1/4-inch depth. It handles a light frost fine, unlike more tender annuals. It reaches maturity in about 75 days and is planted dense, at 3 plants per square foot, so it fills in as a solid patch rather than a scattering of individual plants.
Most racks sell a dwarf blue mix bred for bedding and borders, which is the assumption behind the spacing above. If you want to cut it for bouquets, look for a named tall strain instead, since the dwarf types don’t have the stem length for it.
If you want the plant to reseed itself for next year, leave some blooms on at the end of the season instead of deadheading everything, the seed heads dry, drop, and in the right climate come back on their own the following spring. Deadhead everything and collect a few dried seed heads by hand instead if you’d rather control exactly where it grows each year. Cut blooms also hold up well in a vase, several days longer than most annual cut flowers.
Mildew shows up in crowded plantings
Powdery mildew and rust can appear on crowded plantings, especially later in the season, giving it its full 3-per-square-foot spacing (not tighter) and avoiding wetting the foliage late in the day helps keep it in check. Plants that stop flowering by midsummer are usually just spent from a long bloom run; deadheading spent flowers regularly extends the show, but an early sowing will naturally taper off before a later one does.
A dense pollinator filler, not a dedicated square
Bachelor’s button is a well-known pollinator draw, bringing bees and other beneficial insects into the vegetable beds it’s planted near. See the full companion guide for bachelor’s button. At 3 per square foot, it’s dense enough to work as a border or filler planting in the Garden Designer rather than needing dedicated bed space of its own.
Sources: Tall Blue Boy Organic Centaurea, Johnny’s Selected Seeds.
Companion planting guide for Bachelor's Button (Cornflower) · Find your planting dates
Typically viable in USDA zones 2-11. Not sure your zone? Look it up by ZIP code.
Mature height: 1-3 ft
Method: Either: Start indoors for an earlier harvest, or direct-sow outside for less fuss. Either works.
When to plant bachelor's button (cornflower), by zone
Every zone bachelor's button (cornflower) grows in. Pick your zone in the header and it will be highlighted here. Each zone links to its full page.
| 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 | 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.
See exact start-indoors, direct-sow, and harvest dates for your zone →
How many Bachelor's Button (Cornflower) plants fit per square foot?
Spacing: 3 per square foot (square-foot-gardening spacing). Mature height: 1-3 ft.
Varieties worth considering
- 'Tall Blue Boy': Most seed racks sell a dwarf blue or color mix meant for border filler, which is what the spacing and placement below assume. If you want to cut it for a vase, that's the wrong plant: those dwarf strains top out around a foot. 'Tall Blue Boy' runs 30 to 38 inches with stems long enough to cut, which is why Johnny's sells it specifically for cut-flower use. (source)
- 'Florist Blue Boy': The heirloom Johnny's sells alongside the newer Tall Blue Boy, a longer-established tall blue strain for cutting. Worth comparing if the newer variety isn't available or you want the older, more widely-grown standard. (source)
Why each variety is listed comes from the source shown next to it. We haven't grown these ourselves yet, so treat this as a research-backed starting point, not a personal endorsement. The buy links are separate from those sources: they go to seed suppliers that sell that exact variety, and we may earn a commission on some of them.
Where to buy bachelor's button seeds
Botanical Interests · True Leaf Market · High Mowing Organic Seeds (each supplier's bachelor's button seeds)
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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)
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Growing Bachelor's Button (Cornflower): A cool-tolerant, fast, no-fuss annual that fills a bed densely while pulling in pollinators.
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