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When to Plant Ageratum in Irion 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.

Irion County, Texas is in USDA Zone 8a. The average last spring frost is April 1 and the first fall frost is November 7, giving you a growing season of approximately 220 days.

At an elevation of 1,818 feet, Irion County receives approximately 51.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 100°F, so Ageratum may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Ageratum will need more frequent watering and organic matter to retain nutrients. 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
Irion County, TX (Zone 8a) Long season
220 days
Last Spring Frost April 1
220 growing days
First Fall Frost November 7

Irion County Soil Profile

Soil Type

Sandy Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Ageratum Planting Timeline — Irion County, TX

Ageratum Planting Calendar

Activity When Date Range
Start Indoors February 18 Feb 18 – Mar 4
Transplant Outdoors March 25 Mar 25 – Apr 8
Direct Sow March 25 Mar 25 – Apr 15
Bloom May 20 May 20 – Oct 7

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors Transplant Outdoors Direct Sow
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

Moderate — regular watering

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 8a

📆 Growing Season

220 days in Irion County

Growing Tips for Irion 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 Irion County, TX?

Irion County is in Zone 8a with an average last frost of April 1. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Irion County, TX?

Irion County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is April 1 and first fall frost is November 7.

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Your Irion County Garden Planner — Free

A 22-page printable planner built for Irion 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 Irion County, TX. Local conditions may vary. Last updated: August 2026.

Sources & credits

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