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When to Plant Ageratum in Duval County, TX

Duval County, Texas Zone 9b June

Your June planting checklist for Duval County, Texas

Here's what deserves your attention in Duval County, Texas this month. Everything below is tailored to Zone 9b and timed around your local frost dates.

Avg. last frost February 13
Avg. first frost December 9
Soil temp (4") 75°F
Watering Low
Pest pressure High
Daylight 13.7 hrs
  1. It's harvest week for ageratum

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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.

Duval County, Texas is in USDA Zone 9b. The average last spring frost is February 13 and the first fall frost is December 9, giving you a growing season of approximately 299 days.

At an elevation of 4,259 feet, Duval County receives approximately 55.2 inches of rainfall annually with predominantly loam soil. Summer highs average 102°F, so Ageratum may need afternoon shade and extra watering during peak heat. 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
Duval County, TX (Zone 9b) Year-round
299 days
Last Spring Frost February 13
299 growing days
First Fall Frost December 9

Duval County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.3

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (97 days to spare)
Start indoors: Dec 9 Transplant: Dec 30 🌸 Bloom: Feb 24 – Aug 25
Recommended (50%) ✓ Fits season (82 days to spare)
Start indoors: Jan 2 Transplant: Jan 23 🌸 Bloom: Mar 20 – Sep 18
Safe Start (90%) ✓ Fits season (70 days to spare)
Start indoors: Jan 25 Transplant: Feb 15 🌸 Bloom: Apr 12 – Oct 11

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 Duval County

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

Soil pH

Your soil pH (6.8–7.3) is more alkaline than Ageratum prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

5
successive plantings in your 299-day season

Sow every 6.9 weeks. Last sowing by Sep 25 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 607 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 1.6" 0" ❄️ Dormant
Feb 4.3" 1.7" 2.6" 🚿 Regular watering
Mar 4.3" 4" 0.3" 💧 Light watering
Apr 4.3" 5.3" 0" ✅ Rainfall sufficient
May 4.3" 8.7" 0" ✅ Rainfall sufficient
Jun 4.3" 8.4" 0" ✅ Rainfall sufficient
Jul 4.3" 6.8" 0" ✅ Rainfall sufficient
Aug 4.3" 6" 0" ✅ Rainfall sufficient
Sep 4.3" 5.7" 0" ✅ Rainfall sufficient
Oct 4.3" 3.6" 0.7" 💧 Light watering
Nov 4.3" 1.9" 2.4" 🚿 Regular watering
Dec 4.3" 1.6" 2.7" 🚿 Regular watering

Water needs are for active growing months only (Feb–Dec in Duval 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 ~1,789 GDD — county provides 7,950 GDD Excellent fit

Ageratum Planting Timeline — Duval County, TX

Ageratum Planting Calendar

Activity When Date Range
Start Indoors January 2 Jan 2 – Jan 16
Transplant Outdoors January 23 Jan 23 – Feb 6
Direct Sow January 23 Jan 23 – Feb 13
Bloom March 20 Mar 20 – Sep 18

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors Transplant Outdoors Direct Sow
February Transplant Outdoors Direct Sow
March Bloom
April Bloom
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: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

299 days in Duval County

Growing Tips for Ageratum in Duval County

Direct sow Ageratum outdoors after February 13 in Duval County when soil has warmed and frost danger has passed.

With summer highs reaching 102°F in Duval County, provide afternoon shade for Ageratum and water deeply in the morning.

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 Duval County, TX?

Duval County is in Zone 9b with an average last frost of February 13. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Duval County, TX?

Duval County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 13 and first fall frost is December 9.

🌱

Your Duval County Garden Planner — Free

A 22-page printable planner built for Duval County (Zone 9b). 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 Duval 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.