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When to Plant Coreopsis in Mills County, TX

Mills County, Texas Zone 8b June

Mills County, Texas gardeners: here's your June plan

Your Mills County, Texas garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost March 23
Avg. first frost November 12
Soil temp (4") 71°F
Watering Low
Pest pressure High
Daylight 14 hrs
  1. Pick coreopsis

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Get ahead of July
  • 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.

Mills County, Texas is in USDA Zone 8b. The average last spring frost is March 23 and the first fall frost is November 12, giving you a growing season of approximately 234 days.

At an elevation of 4,208 feet, Mills County receives approximately 61.7 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Coreopsis during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Coreopsis root diseases.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Mills County, TX (Zone 8b) Long season
234 days
Last Spring Frost March 23
234 growing days
First Fall Frost November 12

Mills County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.6

Drainage

Well Drained

Coreopsis Planting Risk Windows

Early Start (70% safe) ✓ Fits season (27 days to spare)
Start indoors: Jan 15 Transplant: Mar 12 🌸 Bloom: May 14 – Oct 8
Recommended (50%) ✓ Fits season (24 days to spare)
Start indoors: Jan 26 Transplant: Mar 23 🌸 Bloom: May 25 – Oct 19
Safe Start (90%) ✓ Fits season (21 days to spare)
Start indoors: Feb 17 Transplant: Apr 14 🌸 Bloom: Jun 16 – Nov 10

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 Mills County

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

Soil pH

Your soil pH (6.7–7.6) overlaps with Coreopsis's range (5.5–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.2%). 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 234-day season

Sow every 6.9 weeks. Last sowing by Aug 24 to harvest before frost.

Coreopsis Water Budget

Plant needs
0.5″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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 1.7" 0" ❄️ Dormant
Feb 2.4" 0" ❄️ Dormant
Mar 2.2" 3.8" 0" ✅ Rainfall sufficient
Apr 2.2" 6.2" 0" ✅ Rainfall sufficient
May 2.2" 10.5" 0" ✅ Rainfall sufficient
Jun 2.2" 9.5" 0" ✅ Rainfall sufficient
Jul 2.2" 7.5" 0" ✅ Rainfall sufficient
Aug 2.2" 7" 0" ✅ Rainfall sufficient
Sep 2.2" 5.6" 0" ✅ Rainfall sufficient
Oct 2.2" 4.2" 0" ✅ Rainfall sufficient
Nov 2.2" 2" 0.2" 💧 Light watering
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Mills 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 ~1,225 GDD — county provides 4,095 GDD Excellent fit

Coreopsis Planting Timeline — Mills County, TX

Coreopsis Planting Calendar

Activity When Date Range
Start Indoors January 26 Jan 26 – Feb 9
Transplant Outdoors March 23 Mar 23 – Apr 6
Direct Sow March 9 Mar 9 – Mar 30
Bloom May 25 May 25 – Oct 19

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors
March Transplant Outdoors Direct Sow
April Transplant Outdoors
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 · Natural rainfall sufficient

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

234 days in Mills County

Growing Tips for Coreopsis in Mills County

Direct sow Coreopsis outdoors after March 23 in Mills County when soil has warmed and frost danger has passed.

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

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 Mills County, TX?

Mills County is in Zone 8b with an average last frost of March 23. Plan your Coreopsis planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mills County, TX?

Mills County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 23 and first fall frost is November 12.

🌱

Your Mills County Garden Planner — Free

A 22-page printable planner built for Mills County (Zone 8b). 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 Mills County, TX. 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.