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When to Plant Ageratum in Franklin 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.

Franklin County, Texas is in USDA Zone 8b. The average last spring frost is March 18 and the first fall frost is November 11, giving you a growing season of approximately 238 days.

At an elevation of 324 feet, Franklin County receives approximately 60 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 97°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
Franklin County, TX (Zone 8b) Long season
238 days
Last Spring Frost March 18
238 growing days
First Fall Frost November 11
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Franklin County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.4-6.3

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 1.9" 0" ❄️ Dormant
Mar 4.3" 4.1" 0.2" 💧 Light watering
Apr 4.3" 5.6" 0" ✅ Rainfall sufficient
May 4.3" 7.9" 0" ✅ Rainfall sufficient
Jun 4.3" 9.9" 0" ✅ Rainfall sufficient
Jul 4.3" 8.3" 0" ✅ Rainfall sufficient
Aug 4.3" 7.1" 0" ✅ Rainfall sufficient
Sep 4.3" 6" 0" ✅ Rainfall sufficient
Oct 4.3" 3.9" 0.4" 💧 Light watering
Nov 4.3" 2.3" 2" 💧 Light watering
Dec 1.6" 0" ❄️ Dormant

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

Ageratum Planting Timeline — Franklin County, TX

Ageratum Planting Calendar

Activity When Date Range
Start Indoors February 4 Feb 4 – Feb 18
Transplant Outdoors March 4 Mar 4 – Mar 18
Direct Sow March 4 Mar 4 – Mar 25
Bloom April 29 Apr 29 – Sep 30

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Transplant Outdoors Direct Sow
April Bloom
May Bloom
June Bloom
July Bloom
August Bloom
September Bloom
October
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 8b

📆 Growing Season

238 days in Franklin County

Growing Tips for Franklin 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 Franklin County, TX?

Franklin County is in Zone 8b with an average last frost of March 18. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Franklin County, TX?

Franklin County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 18 and first fall frost is November 11.

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Your Franklin County Garden Planner — Free

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

Sources & credits

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