When to plant Coreopsis in Fremont County, CO
Fremont County sits in cold Zone 6a. Plant Coreopsis May 30–June 20 for the single annual harvest; the September 25 first frost closes the window.
When to Plant Coreopsis in Fremont County, CO
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.
Fremont County, Colorado is in USDA Zone 6a. The average last spring frost is May 23 and the first fall frost is September 25, giving you a growing season of approximately 125 days.
At an elevation of 6,575 feet, Fremont County receives approximately 18.5 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.
Fremont County Soil Profile
Soil Type
Loam
Soil pH
6.7-8.3
Drainage
Well Drained
Monthly Watering Guide for Coreopsis
Coreopsis needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Coreopsis Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.1" | 0" | ❄️ Dormant |
| Mar | — | 1.6" | 0" | ❄️ Dormant |
| Apr | — | 2.2" | 0" | ❄️ Dormant |
| May | 4.3" | 2" | 2.3" | 🚿 Regular watering |
| Jun | 4.3" | 1.5" | 2.8" | 🚿 Regular watering |
| Jul | 4.3" | 1.4" | 2.9" | 🚿 Regular watering |
| Aug | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| Sep | 4.3" | 1.5" | 2.8" | 🚿 Regular watering |
| Oct | — | 1.7" | 0" | ❄️ Dormant |
| Nov | — | 1.4" | 0" | ❄️ Dormant |
| Dec | — | 1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Fremont County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Coreopsis Planting Timeline — Fremont County, CO
Coreopsis Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 21 | Mar 21 – Apr 4 |
| Transplant Outdoors | May 30 | May 30 – Jun 13 |
| Direct Sow | May 30 | May 30 – Jun 20 |
| Bloom | August 8 | Aug 8 – Nov 28 |
Plant 0.1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| 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 6a
📆 Growing Season
125 days in Fremont County
Growing Tips for Fremont 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 Fremont County, CO?
Fremont County is in Zone 6a with an average last frost of May 23. Plan your Coreopsis planting based on this frost date — see the calendar above for exact timing.
What planting zone is Fremont County, CO?
Fremont County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is May 23 and first fall frost is September 25.
When should I plant Coreopsis in Fremont County, CO?
In Fremont County, CO, plant Coreopsis after the last frost (around May 23) and before the first frost (around September 25). Best results when soil holds above 50°F.
What growing zone is Fremont County, CO for Coreopsis?
Fremont County sits in USDA Zone 6a. Coreopsis grows reliably in zones 3a through 9b, so it's a good fit here.
Can Coreopsis grow in Fremont County's climate?
Yes — Coreopsis grows well in Fremont County's temperate climate. Fremont County averages a 125-day frost-free season, with last frost around May 23 and first frost around September 25.
Your Fremont County Garden Planner — Free
A 22-page printable planner built for Fremont County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.