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When to Plant Ageratum in Cooke County, TX

Ageratum (Ageratum houstonianum), the floss flower, produces clusters of fluffy, powder-puff blooms in the rare sky-blue and lavender tones difficult to find among warm-season annuals. Compact mounding habit makes it ideal as a front-of-border edging plant. Blooms from early summer through fall with minimal deadheading; heat and humidity tolerant once established.

Cooke County, Texas is in USDA Zone 8a. The average last spring frost is March 26 and the first fall frost is November 11, giving you a growing season of approximately 230 days.

At an elevation of 1,818 feet, Cooke County receives approximately 69.5 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Ageratum during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Ageratum root diseases.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Cooke County, TX (Zone 8a) Long season
230 days
Last Spring Frost March 26
230 growing days
First Fall Frost November 11
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Cooke County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.6

Drainage

Well Drained

Monthly Watering Guide for Ageratum

Ageratum needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Ageratum Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 4.3" 4.6" 0" ✅ Rainfall sufficient
Apr 4.3" 8.1" 0" ✅ Rainfall sufficient
May 4.3" 9.9" 0" ✅ Rainfall sufficient
Jun 4.3" 10.8" 0" ✅ Rainfall sufficient
Jul 4.3" 9.9" 0" ✅ Rainfall sufficient
Aug 4.3" 7.5" 0" ✅ Rainfall sufficient
Sep 4.3" 6.7" 0" ✅ Rainfall sufficient
Oct 4.3" 3.9" 0.4" 💧 Light watering
Nov 4.3" 2.2" 2.1" 💧 Light watering
Dec 1.8" 0" ❄️ Dormant

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

Ageratum Planting Timeline — Cooke County, TX

Ageratum Planting Calendar

Activity When Date Range
Start Indoors February 12 Feb 12 – Feb 26
Transplant Outdoors March 19 Mar 19 – Apr 2
Direct Sow March 19 Mar 19 – Apr 9
Bloom May 14 May 14 – Oct 1

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January
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

Moderate — regular watering

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 8a

📆 Growing Season

230 days in Cooke County

Growing Tips for Cooke County

Start seeds indoors 6–8 weeks before last frost — do not cover seed; it needs light to germinate. Can be direct-sown after last frost once soil warms to 60°F. Transplant or thin to proper spacing after frost danger passes. Deadheading isn't strictly required but tidying spent clusters improves appearance. Provide consistent moisture; drought causes premature setting. Avoid deep shade — blooms best in full sun to light afternoon shade.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Ageratum in Cooke County, TX?

Cooke County is in Zone 8a with an average last frost of March 26. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cooke County, TX?

Cooke County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 26 and first fall frost is November 11.

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Your Cooke County Garden Planner — Free

A 22-page printable planner built for Cooke 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 Cooke 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.