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When to Plant Gaillardia (Blanket Flower) in Knox County, TX

Knox County, Texas Zone 8a June

This month in Knox County, Texas

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

Avg. last frost March 24
Avg. first frost November 12
Soil temp (4") 74°F
Watering Low
Pest pressure High
Daylight 14.2 hrs
  1. Bring in the gaillardia (blanket flower)

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

July prep starts now
  • First harvests: gaillardia (blanket flower)

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Gaillardia (Gaillardia aristata), the native blanket flower of the American West, is one of the most floriferous and longest-blooming perennials available — producing cheerful, daisy-like flowers in fiery red, orange, and yellow combinations from early summer through hard frost in most climates. Named for the way its spreading colonies mimic the patterned blankets of Indigenous American weavers, gaillardia thrives in the exact conditions that challenge other perennials: poor, dry, gravelly soil in full sun. An outstanding pollinator plant, attracting bees, butterflies, and finches that feed on its seed heads. Somewhat short-lived (3–5 years) but self-seeds freely to sustain garden colonies.

Knox County, Texas is in USDA Zone 8a. The average last spring frost is March 24 and the first fall frost is November 12, giving you a growing season of approximately 233 days.

At an elevation of 1,847 feet, Knox County receives approximately 51.2 inches of rainfall annually with predominantly loam soil. Summer highs average 93°F, providing good warmth for Gaillardia (Blanket Flower) during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Gaillardia (Blanket Flower) root diseases.

Perennial Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting
Knox County, TX (Zone 8a) Long season
233 days
Last Spring Frost March 24
233 growing days
First Fall Frost November 12
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Knox County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.2

Drainage

Well Drained

Gaillardia (Blanket Flower) Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Jan 27 Transplant: Mar 10 🌸 Bloom: May 19 – Nov 3
Recommended (50%) ✓ Fits season (2 days to spare)
Start indoors: Feb 3 Transplant: Mar 17 🌸 Bloom: May 26 – Nov 10
Safe Start (90%) ✗ May not fit
Start indoors: Feb 23 Transplant: Apr 6 🌸 Bloom: Jun 15 – 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 Knox County

How your county's soil matches Gaillardia (Blanket Flower)'s growing requirements.

Soil pH

Your soil pH (6.4–7.2) overlaps with Gaillardia (Blanket Flower)'s range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in Knox County is excellent for Gaillardia (Blanket Flower) — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is low (1.9%). Add 2-3 inches of compost before planting Gaillardia (Blanket Flower).

How to Plant Gaillardia (Blanket Flower)

0.1"
Planting Depth
12"
Between Plants
18"
Between Rows

Succession Planting Gaillardia (Blanket Flower)

3
successive plantings in your 233-day season

Sow every 8 weeks. Last sowing by Aug 04 to harvest before frost.

Gaillardia (Blanket Flower) Water Budget

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

Monthly Watering Guide for Gaillardia (Blanket Flower)

Gaillardia (Blanket Flower) 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 Gaillardia (Blanket Flower) Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 2.1" 0" ❄️ Dormant
Mar 2.2" 3.2" 0" ✅ Rainfall sufficient
Apr 2.2" 6.4" 0" ✅ Rainfall sufficient
May 2.2" 6.7" 0" ✅ Rainfall sufficient
Jun 2.2" 7.3" 0" ✅ Rainfall sufficient
Jul 2.2" 6.5" 0" ✅ Rainfall sufficient
Aug 2.2" 5.9" 0" ✅ Rainfall sufficient
Sep 2.2" 5.4" 0" ✅ Rainfall sufficient
Oct 2.2" 3.3" 0" ✅ Rainfall sufficient
Nov 2.2" 1.8" 0.4" 💧 Light watering
Dec 1.3" 0" ❄️ Dormant

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

Gaillardia (Blanket Flower) 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.

Gaillardia (Blanket Flower) needs ~1,679 GDD — county provides 4,601 GDD Excellent fit

Gaillardia (Blanket Flower) Planting Timeline — Knox County, TX

Gaillardia (Blanket Flower) Planting Calendar

Activity When Date Range
Start Indoors February 3 Feb 3 – Feb 17
Transplant Outdoors March 17 Mar 17 – Mar 31
Direct Sow March 17 Mar 17 – Apr 7
Bloom May 26 May 26 – Nov 10

Plant 0.1" deep · 12" apart · Rows 18" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

233 days in Knox County

Growing Tips for Gaillardia (Blanket Flower) in Knox County

Direct sow Gaillardia (Blanket Flower) outdoors after March 24 in Knox County when soil has warmed and frost danger has passed.

Common pests for Gaillardia (Blanket Flower) in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 6–8 weeks before last frost or direct-sow after last frost. Seeds need light to germinate — press onto soil surface without covering, or cover very lightly (1/8 inch). Transplant after last frost when soil has warmed. Lean, well-drained soil is essential — rich or wet soil causes sprawl and root rot. Deadhead spent blooms to prolong the season, but leave some heads for self-seeding to renew the planting. Divide every 2–3 years in spring to maintain vigor. Drought-tolerant once established; overwatering is more damaging than underwatering. Year 2+ plants deliver the fullest multi-season bloom.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Gaillardia (Blanket Flower) in Knox County, TX?

Knox County is in Zone 8a with an average last frost of March 24. Plan your Gaillardia (Blanket Flower) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Knox County, TX?

Knox County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 24 and first fall frost is November 12.

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Your Knox County Garden Planner — Free

A 22-page printable planner built for Knox 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 Knox 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.