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When to Plant Coreopsis in Tom Green County, TX

Tom Green County, Texas Zone 8a June

What to do in June

Here's what deserves your attention in Tom Green County, Texas this month. Everything below is tailored to Zone 8a and timed around your local frost dates.

Avg. last frost March 25
Avg. first frost November 12
Soil temp (4") 68°F
Watering High
Pest pressure High
Daylight 14 hrs
  1. Pick coreopsis

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

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.

Tom Green County, Texas is in USDA Zone 8a. The average last spring frost is March 25 and the first fall frost is November 12, giving you a growing season of approximately 232 days.

At an elevation of 4,366 feet, Tom Green County receives approximately 52.3 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 102°F, so Coreopsis may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Coreopsis will need more frequent watering and organic matter to retain nutrients. 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
Tom Green County, TX (Zone 8a) Long season
232 days
Last Spring Frost March 25
232 growing days
First Fall Frost November 12
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Tom Green County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.2-8.3

Drainage

Well Drained

Coreopsis Planting Risk Windows

Early Start (70% safe) ✓ Fits season (26 days to spare)
Start indoors: Jan 15 Transplant: Mar 12 🌸 Bloom: May 14 – Oct 8
Recommended (50%) ✓ Fits season (22 days to spare)
Start indoors: Jan 28 Transplant: Mar 25 🌸 Bloom: May 27 – Oct 21
Safe Start (90%) ✓ Fits season (16 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 Tom Green County

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

Soil pH

Your soil pH (7.2–8.3) is more alkaline than Coreopsis prefers (5.5–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Tom Green County warms quickly in spring but drains fast. Coreopsis will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Coreopsis.

Organic Matter

Organic matter is low (0.9%). Add 2-3 inches of compost before planting Coreopsis.

How to Plant Coreopsis

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

Succession Planting Coreopsis

4
successive plantings in your 232-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
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 3" 0" ❄️ Dormant
Feb 3.1" 0" ❄️ Dormant
Mar 2.2" 3.1" 0" ✅ Rainfall sufficient
Apr 2.2" 1.5" 0.7" 💧 Light watering
May 2.2" 1.3" 0.9" 💧 Light watering
Jun 2.2" 1.9" 0.3" 💧 Light watering
Jul 2.2" 9.5" 0" ✅ Rainfall sufficient
Aug 2.2" 10.3" 0" ✅ Rainfall sufficient
Sep 2.2" 7.4" 0" ✅ Rainfall sufficient
Oct 2.2" 4.8" 0" ✅ Rainfall sufficient
Nov 2.2" 2.7" 0" ✅ Rainfall sufficient
Dec 3.9" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Tom Green 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 ~1,855 GDD — county provides 6,148 GDD Excellent fit

Coreopsis Planting Timeline — Tom Green County, TX

Coreopsis Planting Calendar

Activity When Date Range
Start Indoors January 28 Jan 28 – Feb 11
Transplant Outdoors March 25 Mar 25 – Apr 8
Direct Sow March 18 Mar 18 – Apr 8
Bloom May 27 May 27 – Oct 21

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 Direct Sow
May Bloom
June Bloom
July Bloom
August Bloom
September Bloom
October Bloom
November
December
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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: too_alkaline

🗺️ USDA Zone

Zone 8a

📆 Growing Season

232 days in Tom Green County

Growing Tips for Coreopsis in Tom Green County

Direct sow Coreopsis outdoors after March 25 in Tom Green County when soil has warmed and frost danger has passed.

Sandy soil in Tom Green County dries quickly — mulch Coreopsis with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 102°F in Tom Green 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.

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 Tom Green County, TX?

Tom Green County is in Zone 8a with an average last frost of March 25. Plan your Coreopsis planting based on this frost date — see the calendar above for exact timing.

What planting zone is Tom Green County, TX?

Tom Green County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 25 and first fall frost is November 12.

🌱

Your Tom Green County Garden Planner — Free

A 22-page printable planner built for Tom Green County (Zone 8a). 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 Tom Green 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.