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When to plant Coreopsis in Madera County, CA

Aim to plant Coreopsis in Madera County on or after April 4; the window stays open through April 25. Madera County's 205-day frost-free season gives you enough for a full main crop and a short fall succession.

When to Plant Coreopsis in Madera County, CA

Madera County, California Zone 9a June

Your June planting checklist for Madera County, California

Each item below is timed to Madera County, California's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 18
Avg. first frost November 9
Soil temp (4") 87°F
Watering Critical
Pest pressure High
Daylight 14.5 hrs
  1. Start coreopsis indoors

    Label every cell. You will absolutely forget which is which otherwise.

  2. Pick coreopsis

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

July prep starts now
  • First harvests: coreopsis

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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.

Madera County, California is in USDA Zone 9a. The average last spring frost is April 18 and the first fall frost is November 9, giving you a growing season of approximately 205 days.

At an elevation of 187 feet, Madera County receives approximately 14.5 inches of rainfall annually with predominantly loam soil. Summer highs average 104°F, so Coreopsis may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Coreopsis successfully. Mulch heavily to conserve soil moisture.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Madera County, CA (Zone 9a) Long season
205 days
Last Spring Frost April 18
205 growing days
First Fall Frost November 9

Madera County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.8

Drainage

Well Drained

Coreopsis Planting Risk Windows

Early Start (70% safe) ✓ Fits season (24 days to spare)
Start indoors: Jan 27 Transplant: Mar 10 🌸 Bloom: May 5 – Oct 6
Recommended (50%) ✓ Fits season (9 days to spare)
Start indoors: Feb 21 Transplant: Apr 4 🌸 Bloom: May 30 – Oct 31
Safe Start (90%) ✓ Fits season (3 days to spare)
Start indoors: Mar 23 Transplant: May 4 🌸 Bloom: Jun 29 – Nov 30

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 Madera County

How your county's soil matches Coreopsis's growing requirements.

Soil pH

Your soil pH (6.2–7.8) overlaps with Coreopsis's range (5.5–7.5), though not a perfect match.

Soil Texture

The loam soil in Madera County is excellent for Coreopsis — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Coreopsis.

How to Plant Coreopsis

0.1"
Planting Depth
18"
Between Plants
24"
Between Rows

Succession Planting Coreopsis

4
successive plantings in your 205-day season

Sow every 6.9 weeks. Last sowing by Aug 21 to harvest before frost.

Coreopsis Water Budget

Plant needs
0.5″/week
Rainfall provides
0.3″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 444 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 2.6" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 2.2" 1.3" 0.9" 💧 Light watering
May 2.2" 0.4" 1.8" 🚿 Regular watering
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 2.2" 0.1" 2.1" 🚿 Regular watering
Oct 2.2" 0.7" 1.5" 🚿 Regular watering
Nov 2.2" 1.4" 0.8" 💧 Light watering
Dec 2.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Madera 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 needs ~1,960 GDD — county provides 5,740 GDD Excellent fit

Coreopsis Planting Timeline — Madera County, CA

Coreopsis Planting Calendar

Activity When Date Range
Start Indoors February 21 Feb 21 – Mar 7
Transplant Outdoors April 4 Apr 4 – Apr 18
Direct Sow April 4 Apr 4 – Apr 25
Bloom May 30 May 30 – Oct 31

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April Transplant Outdoors Direct Sow
May Bloom
June Bloom
July Bloom
August Bloom
September Bloom
October Bloom
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

205 days in Madera County

Growing Tips for Coreopsis in Madera County

Direct sow Coreopsis outdoors after April 18 in Madera County when soil has warmed and frost danger has passed.

With summer highs reaching 104°F in Madera County, provide afternoon shade for Coreopsis and water deeply in the morning.

Common pests for Coreopsis in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

Madera County receives only 14" 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 →

Frequently Asked Questions

When should I plant Coreopsis in Madera County, CA?

Madera County is in Zone 9a with an average last frost of April 18. Plan your Coreopsis planting based on this frost date — see the calendar above for exact timing.

What planting zone is Madera County, CA?

Madera County, California is in USDA Hardiness Zone 9a. The average last spring frost is April 18 and first fall frost is November 9.

When should I plant Coreopsis in Madera County, CA?

In Madera County, CA, plant Coreopsis after the last frost (around April 18) and before the first frost (around November 9). Best results when soil holds above 50°F.

What growing zone is Madera County, CA for Coreopsis?

Madera County sits in USDA Zone 9a. Coreopsis grows reliably in zones 3a through 9b, so it's a good fit here.

Can Coreopsis grow in Madera County's climate?

Yes — Coreopsis grows well in Madera County's temperate climate. Madera County averages a 205-day frost-free season, with last frost around April 18 and first frost around November 9.

🌱

Your Madera County Garden Planner — Free

A 22-page printable planner built for Madera County (Zone 9a). 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 Madera County, CA. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.