When to plant Coreopsis in Treasure County, MT
Plant Coreopsis in Treasure County, between May 18 and June 8 — the only viable window. Zone 4b's short season (143 frost-free days) rules out a fall crop.
When to Plant Coreopsis in Treasure County, MT
Coreopsis (Tickseed) is a cheerful, long-blooming native perennial that produces a continuous flush of bright yellow, gold, or bi-colored daisy-like flowers from early summer well into fall. One of the most reliable cut-and-come-again bloomers in the perennial garden, it thrives in hot, dry, sunny conditions and poor soil where many competitors struggle. An invaluable nectar source for native bees and butterflies, and a butterfly host plant for several species.
Treasure County, Montana is in USDA Zone 4b. The average last spring frost is May 11 and the first fall frost is October 1, giving you a growing season of approximately 143 days.
At an elevation of 6,726 feet, Treasure County receives approximately 17.1 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Coreopsis to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Coreopsis successfully. Mulch heavily to conserve soil moisture.
Treasure County Soil Profile
Soil Type
Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Coreopsis Planting Timeline — Treasure County, MT
Coreopsis Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 2 | Mar 2 – Mar 16 |
| Transplant Outdoors | May 25 | May 25 – Jun 8 |
| Direct Sow | May 18 | May 18 – Jun 8 |
| Bloom | August 10 | Aug 10 – Nov 2 |
Plant 0.1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | — |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | Bloom |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
60–80 days
🧪 Soil pH
Needs 5.5–7.5 · Your soil: N/A
🗺️ USDA Zone
Zone 4b
📆 Growing Season
143 days in Treasure County
Growing Tips for Treasure County
Start seeds indoors 8–10 weeks before last frost or direct sow after last frost. Seeds germinate easily without stratification. Thrives in poor to average, well-drained soil — rich soil promotes foliage over flowers. Drought tolerant once established; overwatering is the most common mistake. Deadhead spent blooms to maintain continuous flowering through the season. Shear plants by one-third in midsummer for a fresh flush of late-season blooms. Year 2+ plants bloom most heavily. Divide every 2–3 years in early spring to rejuvenate crowded clumps.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Coreopsis in Other Locations
Frequently Asked Questions
When should I plant Coreopsis in Treasure County, MT?
Treasure County is in Zone 4b with an average last frost of May 11. Plan your Coreopsis planting based on this frost date — see the calendar above for exact timing.
What planting zone is Treasure County, MT?
Treasure County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 11 and first fall frost is October 1.
When should I plant Coreopsis in Treasure County, MT?
In Treasure County, MT, plant Coreopsis after the last frost (around May 11) and before the first frost (around October 1). Best results when soil holds above 50°F.
What growing zone is Treasure County, MT for Coreopsis?
Treasure County sits in USDA Zone 4b. Coreopsis grows reliably in zones 3a through 9b, so it's a good fit here.
Can Coreopsis grow in Treasure County's climate?
Yes — Coreopsis grows well in Treasure County's temperate climate. Treasure County averages a 143-day frost-free season, with last frost around May 11 and first frost around October 1.
Your Treasure County Garden Planner — Free
A 22-page printable planner built for Treasure County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.