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When to Plant Bachelor's Button in Hawaii

Bachelor's Button (Centaurea cyanus), also called cornflower, is a carefree cool-season annual best known for its vivid cobalt-blue flowers — one of the truest blues in the annual garden. It tolerates light frosts, self-seeds prolifically, and thrives in poor to average soils. A traditional cut flower and pollinator magnet, it has been cultivated in gardens for centuries.

Hawaii spans USDA hardiness zones 11a (with planting data available), so planting dates vary by your location within the state. Click your zone below for the most accurate dates.

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Click your county for exact Bachelor's Button planting dates based on your local frost dates.

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Bachelor's Button Planting Calendar for Hawaii

Zone 11a ~364 day growing season · Full guide →

Last frost: January 1 · First frost: December 31 · 364 day season

Activity When Date Range
Transplant Outdoors November 6 Nov 6 – Nov 20
Direct Sow October 9 Oct 9 – Oct 30
Bloom December 25 Dec 25 – Mar 26
Fall Sowing September 24 Sep 24 – Oct 8

Growing Tips for Hawaii

Direct-sow in early spring as soon as soil can be worked; seeds need a brief cold period for best germination (refrigerate for a few days before planting if spring arrives quickly). In zones 6+, fall-sow for the earliest spring bloom. Thin to 12 inches; do not over-fertilize — too much nitrogen produces foliage at the expense of flowers. Deadhead to prolong blooming or allow self-seeding for a naturalized colony.

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Frequently Asked Questions

When should I plant Bachelor's Button in Hawaii?

Planting dates for Bachelor's Button in Hawaii depend on your USDA zone. Hawaii spans zones 11a. Check the planting calendar above for your specific zone's frost dates and planting windows.

What zone is Hawaii for planting?

Hawaii contains USDA hardiness zones 11a. Your specific zone depends on your location within the state — northern and higher-elevation areas are in colder zones, while southern and coastal areas are warmer.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals, University Cooperative Extension planting guides. Last updated: June 2026.