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When to plant Coreopsis in Mason County, MI

Mason County sits in cold Zone 6a. Plant Coreopsis May 22–June 12 for the single annual harvest; the October 7 first frost closes the window.

When to Plant Coreopsis in Mason County, MI

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.

Mason County, Michigan is in USDA Zone 6a. The average last spring frost is May 15 and the first fall frost is October 7, giving you a growing season of approximately 145 days.

At an elevation of 1,318 feet, Mason County receives approximately 34.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Coreopsis during the growing season.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Mason County, MI (Zone 6a) Short season
145 days
Last Spring Frost May 15
145 growing days
First Fall Frost October 7

Mason County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.3

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 1.3" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 3.1" 0" ❄️ Dormant
May 4.3" 3.3" 1" 💧 Light watering
Jun 4.3" 4.5" 0" ✅ Rainfall sufficient
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 3.3" 1" 💧 Light watering
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 2.1" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Mason County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Coreopsis Planting Timeline — Mason County, MI

Coreopsis Planting Calendar

Activity When Date Range
Start Indoors March 13 Mar 13 – Mar 27
Transplant Outdoors May 22 May 22 – Jun 5
Direct Sow May 22 May 22 – Jun 12
Bloom July 31 Jul 31 – Nov 20

Plant 0.1" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July Bloom
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

145 days in Mason County

Growing Tips for Mason 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 →

Frequently Asked Questions

When should I plant Coreopsis in Mason County, MI?

Mason County is in Zone 6a with an average last frost of May 15. Plan your Coreopsis planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mason County, MI?

Mason County, Michigan is in USDA Hardiness Zone 6a. The average last spring frost is May 15 and first fall frost is October 7.

When should I plant Coreopsis in Mason County, MI?

In Mason County, MI, plant Coreopsis after the last frost (around May 15) and before the first frost (around October 7). Best results when soil holds above 50°F.

What growing zone is Mason County, MI for Coreopsis?

Mason 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 Mason County's climate?

Yes — Coreopsis grows well in Mason County's temperate climate. Mason County averages a 145-day frost-free season, with last frost around May 15 and first frost around October 7.

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Your Mason County Garden Planner — Free

A 22-page printable planner built for Mason 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.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Mason County, MI. Local conditions may vary. Last updated: July 2026.

Sources & credits

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