When to plant Coreopsis in Mono County, CA
Mono County sits in cold Zone 6b. Plant Coreopsis June 18–July 9 for the single annual harvest; the August 20 first frost closes the window.
When to Plant Coreopsis in Mono County, CA
This month in Mono County, California
A quick June briefing for Mono County, California gardeners — what's urgent, what's next, and what can wait.
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Time to transplant coreopsis
Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.
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Scatter coreopsis into prepared beds
Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.
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.
Mono County, California is in USDA Zone 6b. The average last spring frost is June 18 and the first fall frost is August 20, giving you a growing season of approximately 63 days.
At an elevation of 2,381 feet, Mono County receives approximately 13.3 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.
Mono County Soil Profile
Soil Type
Loam
Soil pH
6-7.5
Drainage
Well Drained
Coreopsis Planting Risk Windows
Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.
Soil Compatibility in Mono County
How your county's soil matches Coreopsis's growing requirements.
Soil pH
Your soil pH (6.0–7.5) is within Coreopsis's preferred range (5.5–7.5).
Soil Texture
The loam soil in Mono County is excellent for Coreopsis — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.5%). Annual compost additions will help Coreopsis.
How to Plant Coreopsis
Coreopsis Water Budget
Water stress score is 10/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Coreopsis
Coreopsis needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.
| Month | Coreopsis Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 2.7" | 0" | ❄️ Dormant |
| Feb | — | 3.1" | 0" | ❄️ Dormant |
| Mar | — | 1.9" | 0" | ❄️ Dormant |
| Apr | — | 1" | 0" | ❄️ Dormant |
| May | — | 0.3" | 0" | ❄️ Dormant |
| Jun | 2.2" | 0.1" | 2.1" | 🚿 Regular watering |
| Jul | 2.2" | 0" | 2.2" | 🚿 Regular watering |
| Aug | 2.2" | 0" | 2.2" | 🚿 Regular watering |
| Sep | — | 0.2" | 0" | ❄️ Dormant |
| Oct | — | 0.6" | 0" | ❄️ Dormant |
| Nov | — | 1.1" | 0" | ❄️ Dormant |
| Dec | — | 2.4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Aug in Mono County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Coreopsis Heat Requirements (GDD)
What are Growing Degree Days (GDD)?
Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.
Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.
Coreopsis Planting Timeline — Mono County, CA
Coreopsis Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 16 | Apr 16 – Apr 30 |
| Transplant Outdoors | June 25 | Jun 25 – Jul 9 |
| Direct Sow | June 18 | Jun 18 – Jul 9 |
| Bloom | September 3 | Sep 3 – Dec 31 |
Plant 0.1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | — |
| June | Transplant Outdoors Direct Sow |
| July | Transplant Outdoors Direct Sow |
| August | — |
| September | Bloom |
| October | Bloom |
| November | Bloom |
| December | Bloom |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · Natural rainfall sufficient
📅 Days to Maturity
60–80 days
🧪 Soil pH
Needs 5.5–7.5 · Your soil: ideal
🗺️ USDA Zone
Zone 6b
📆 Growing Season
63 days in Mono County
Growing Tips for Coreopsis in Mono County
Direct sow Coreopsis outdoors after June 18 in Mono County when soil has warmed and frost danger has passed.
Your 63.0-day growing season in Mono County is tight for Coreopsis (60.0-80.0 days to maturity). Start indoors and choose early-maturing varieties.
Common pests for Coreopsis in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
Mono County receives only 13" of rain annually. Coreopsis needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
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 Mono County, CA?
Mono County is in Zone 6b with an average last frost of June 18. Plan your Coreopsis planting based on this frost date — see the calendar above for exact timing.
What planting zone is Mono County, CA?
Mono County, California is in USDA Hardiness Zone 6b. The average last spring frost is June 18 and first fall frost is August 20.
When should I plant Coreopsis in Mono County, CA?
In Mono County, CA, plant Coreopsis after the last frost (around June 18) and before the first frost (around August 20). Best results when soil holds above 50°F.
What growing zone is Mono County, CA for Coreopsis?
Mono County sits in USDA Zone 6b. Coreopsis grows reliably in zones 3a through 9b, so it's a good fit here.
Can Coreopsis grow in Mono County's climate?
Yes — Coreopsis grows well in Mono County's temperate climate. Mono County averages a 63-day frost-free season, with last frost around June 18 and first frost around August 20.
Your Mono County Garden Planner — Free
A 22-page printable planner built for Mono County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.