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When to Plant Ageratum in Willacy County, TX

Willacy County, Texas Zone 10a July

Your July gardening checklist

Each item below is timed to Willacy County, Texas's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost February 4
Avg. first frost December 22
Soil temp (4") 95°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Pick ageratum

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

Before August arrives, get these ready
  • 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.

Willacy County, Texas is in USDA Zone 10a. The average last spring frost is February 4 and the first fall frost is December 22, giving you a growing season of approximately 321 days.

At an elevation of 1,085 feet, Willacy County receives approximately 65.9 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
Willacy County, TX (Zone 10a) Year-round
321 days
Last Spring Frost February 4
321 growing days
First Fall Frost December 22

Willacy County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.3

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (116 days to spare)
Start indoors: Dec 6 Transplant: Dec 13 🌸 Bloom: Feb 7 – Aug 22
Recommended (50%) ✓ Fits season (104 days to spare)
Start indoors: Dec 24 Transplant: Dec 31 🌸 Bloom: Feb 25 – Sep 9
Safe Start (90%) ✓ Fits season (81 days to spare)
Start indoors: Jan 21 Transplant: Jan 28 🌸 Bloom: Mar 25 – Oct 7

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 Willacy County

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

Soil pH

Your soil pH (6.5–7.3) overlaps with Ageratum's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Ageratum.

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

6
successive plantings in your 321-day season

Sow every 6.9 weeks. Last sowing by Oct 08 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 1,515 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.7" 0" ❄️ Dormant
Feb 4.3" 2.3" 2" 💧 Light watering
Mar 4.3" 4.4" 0" ✅ Rainfall sufficient
Apr 4.3" 6.4" 0" ✅ Rainfall sufficient
May 4.3" 9.5" 0" ✅ Rainfall sufficient
Jun 4.3" 9.7" 0" ✅ Rainfall sufficient
Jul 4.3" 9" 0" ✅ Rainfall sufficient
Aug 4.3" 8.5" 0" ✅ Rainfall sufficient
Sep 4.3" 6.3" 0" ✅ Rainfall sufficient
Oct 4.3" 3.8" 0.5" 💧 Light watering
Nov 4.3" 2.6" 1.7" 💧 Light watering
Dec 4.3" 1.8" 2.5" 🚿 Regular watering

Water needs are for active growing months only (Feb–Dec in Willacy 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 8,533 GDD Excellent fit

Ageratum Planting Timeline — Willacy County, TX

Ageratum Planting Calendar

Activity When Date Range
Start Indoors December 24 Dec 24 – Jan 7
Transplant Outdoors December 31 Dec 31 – Jan 14
Direct Sow December 31 Dec 31 – Jan 21
Bloom February 25 Feb 25 – Sep 9

· 8" apart · Rows 10" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 10a

📆 Growing Season

321 days in Willacy County

Growing Tips for Ageratum in Willacy County

Direct sow Ageratum outdoors after February 04 in Willacy County when soil has warmed and frost danger has passed.

With summer highs reaching 102°F in Willacy 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 Willacy County, TX?

Willacy County is in Zone 10a with an average last frost of February 4. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Willacy County, TX?

Willacy County, Texas is in USDA Hardiness Zone 10a. The average last spring frost is February 4 and first fall frost is December 22.

🌱

Your Willacy County Garden Planner — Free

A 22-page printable planner built for Willacy County (Zone 10a). 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 Willacy County, TX. Local conditions may vary. Last updated: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.