When to plant Bachelor's Button in Clark County, ID
Clark County sits in cold Zone 5b. Plant Bachelor's Button May 17–June 7 for the single annual harvest; the September 10 first frost closes the window.
When to Plant Bachelor's Button in Clark County, ID
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.
Clark County, Idaho is in USDA Zone 5b. The average last spring frost is June 7 and the first fall frost is September 10, giving you a growing season of approximately 95 days.
At an elevation of 7,493 feet, Clark County receives approximately 21.9 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Bachelor's Button to ensure they mature before fall.
Clark County Soil Profile
Soil Type
Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Bachelor's Button Planting Timeline — Clark County, ID
Bachelor's Button Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 26 | Apr 26 – May 10 |
| Transplant Outdoors | June 7 | Jun 7 – Jun 21 |
| Direct Sow | May 17 | May 17 – Jun 7 |
| Bloom | August 9 | Aug 9 – Oct 25 |
Plant 0.3" deep · 12" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Start Indoors Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | — |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7.5 · Your soil: N/A
🗺️ USDA Zone
Zone 5b
📆 Growing Season
95 days in Clark County
Growing Tips for Clark County
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.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Bachelor's Button in Other Locations
Frequently Asked Questions
When should I plant Bachelor's Button in Clark County, ID?
Clark County is in Zone 5b with an average last frost of June 7. Plan your Bachelor's Button planting based on this frost date — see the calendar above for exact timing.
What planting zone is Clark County, ID?
Clark County, Idaho is in USDA Hardiness Zone 5b. The average last spring frost is June 7 and first fall frost is September 10.
When should I plant Bachelor's Button in Clark County, ID?
In Clark County, ID, plant Bachelor's Button after the last frost (around June 7) and before the first frost (around September 10). Best results when soil holds above 50°F.
What growing zone is Clark County, ID for Bachelor's Button?
Clark County sits in USDA Zone 5b. Bachelor's Button grows reliably in zones 2a through 11b, so it's a good fit here.
Can Bachelor's Button grow in Clark County's climate?
Yes — Bachelor's Button grows well in Clark County's temperate climate. Clark County averages a 95-day frost-free season, with last frost around June 7 and first frost around September 10.
Your Clark County Garden Planner — Free
A 22-page printable planner built for Clark County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.