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When to Plant Ageratum in Kerr County, TX

Kerr County, Texas Zone 8b June

Kerr County, Texas gardeners: here's your June plan

Welcome to June in Zone 8b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost March 24
Avg. first frost November 11
Soil temp (4") 75°F
Watering Low
Pest pressure High
Daylight 13.9 hrs
  1. It's harvest week for ageratum

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

July prep starts now
  • 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.

Kerr County, Texas is in USDA Zone 8b. The average last spring frost is March 24 and the first fall frost is November 11, giving you a growing season of approximately 232 days.

At an elevation of 3,907 feet, Kerr County receives approximately 52 inches of rainfall annually with predominantly loam soil. Summer highs average 93°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
Kerr County, TX (Zone 8b) Long season
232 days
Last Spring Frost March 24
232 growing days
First Fall Frost November 11
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Kerr County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.6

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (37 days to spare)
Start indoors: Jan 29 Transplant: Feb 26 🌸 Bloom: Apr 23 – Sep 24
Recommended (50%) ✓ Fits season (36 days to spare)
Start indoors: Feb 10 Transplant: Mar 10 🌸 Bloom: May 5 – Oct 6
Safe Start (90%) ✓ Fits season (30 days to spare)
Start indoors: Mar 5 Transplant: Apr 2 🌸 Bloom: May 28 – Oct 29

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 Kerr County

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

Soil pH

Your soil pH (6.4–7.6) overlaps with Ageratum's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

4
successive plantings in your 232-day season

Sow every 6.9 weeks. Last sowing by Aug 28 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 121 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 1.2" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 4.3" 3.4" 0.9" 💧 Light watering
Apr 4.3" 5.7" 0" ✅ Rainfall sufficient
May 4.3" 6.7" 0" ✅ Rainfall sufficient
Jun 4.3" 9.2" 0" ✅ Rainfall sufficient
Jul 4.3" 7.3" 0" ✅ Rainfall sufficient
Aug 4.3" 6.1" 0" ✅ Rainfall sufficient
Sep 4.3" 4.8" 0" ✅ Rainfall sufficient
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 4.3" 1.7" 2.6" 🚿 Regular watering
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Kerr 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 ~1,333 GDD — county provides 4,582 GDD Excellent fit

Ageratum Planting Timeline — Kerr County, TX

Ageratum Planting Calendar

Activity When Date Range
Start Indoors February 10 Feb 10 – Feb 24
Transplant Outdoors March 10 Mar 10 – Mar 24
Direct Sow March 10 Mar 10 – Mar 31
Bloom May 5 May 5 – Oct 6

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Transplant Outdoors Direct Sow
April
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

1"/week · Only during dry spells

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

232 days in Kerr County

Growing Tips for Ageratum in Kerr County

Direct sow Ageratum outdoors after March 24 in Kerr 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 Kerr County, TX?

Kerr County is in Zone 8b with an average last frost of March 24. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kerr County, TX?

Kerr County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 24 and first fall frost is November 11.

🌱

Your Kerr County Garden Planner — Free

A 22-page printable planner built for Kerr 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 Kerr 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.