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When to Plant Ageratum in Runnels County, TX

Runnels County, Texas Zone 8a June

Your June gardening checklist

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Runnels County, Texas.

Avg. last frost March 19
Avg. first frost November 15
Soil temp (4") 67°F
Watering Low
Pest pressure High
Daylight 14.1 hrs
  1. Harvest ageratum as they ripen

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

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  • First harvests: ageratum

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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.

Runnels County, Texas is in USDA Zone 8a. The average last spring frost is March 19 and the first fall frost is November 15, giving you a growing season of approximately 241 days.

At an elevation of 4,833 feet, Runnels County receives approximately 47.6 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Ageratum during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Runnels County, TX (Zone 8a) Long season
241 days
Last Spring Frost March 19
241 growing days
First Fall Frost November 15

Runnels County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.1

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (56 days to spare)
Start indoors: Jan 26 Transplant: Mar 2 🌸 Bloom: Apr 27 – Sep 14
Recommended (50%) ✓ Fits season (52 days to spare)
Start indoors: Feb 5 Transplant: Mar 12 🌸 Bloom: May 7 – Sep 24
Safe Start (90%) ✓ Fits season (44 days to spare)
Start indoors: Mar 1 Transplant: Apr 5 🌸 Bloom: May 31 – Oct 18

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 Runnels County

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

Soil pH

Your soil pH (6.3–7.1) overlaps with Ageratum's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in Runnels County is excellent for Ageratum — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is low (2.0%). Add 2-3 inches of compost before planting Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

4
successive plantings in your 241-day season

Sow every 6.9 weeks. Last sowing by Sep 01 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 366 gal / 100 sq ft

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" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 4.3" 3" 1.3" 💧 Light watering
Apr 4.3" 4.9" 0" ✅ Rainfall sufficient
May 4.3" 7.4" 0" ✅ Rainfall sufficient
Jun 4.3" 8.1" 0" ✅ Rainfall sufficient
Jul 4.3" 6.3" 0" ✅ Rainfall sufficient
Aug 4.3" 5.1" 0" ✅ Rainfall sufficient
Sep 4.3" 4.2" 0.1" 💧 Light watering
Oct 4.3" 3.2" 1.1" 💧 Light watering
Nov 4.3" 1.5" 2.8" 🚿 Regular watering
Dec 1.3" 0" ❄️ Dormant

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

Ageratum 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.

Ageratum needs ~1,181 GDD — county provides 4,217 GDD Excellent fit

Ageratum Planting Timeline — Runnels County, TX

Ageratum Planting Calendar

Activity When Date Range
Start Indoors February 5 Feb 5 – Feb 19
Transplant Outdoors March 12 Mar 12 – Mar 26
Direct Sow March 12 Mar 12 – Apr 2
Bloom May 7 May 7 – Sep 24

· 8" apart · Rows 10" 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
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

241 days in Runnels County

Growing Tips for Ageratum in Runnels County

Direct sow Ageratum outdoors after March 19 in Runnels County when soil has warmed and frost danger has passed.

Common pests for Ageratum 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 — 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 Runnels County, TX?

Runnels County is in Zone 8a with an average last frost of March 19. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Runnels County, TX?

Runnels County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 19 and first fall frost is November 15.

🌱

Your Runnels County Garden Planner — Free

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

Sources & credits

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