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When to Plant Ageratum in Brooks County, TX

Brooks County, Texas Zone 9b June

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

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

Avg. last frost February 10
Avg. first frost December 13
Soil temp (4") 81°F
Watering Low
Pest pressure High
Daylight 13.7 hrs
  1. Basket week: ageratum

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

Looking ahead to July
  • 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.

Brooks County, Texas is in USDA Zone 9b. The average last spring frost is February 10 and the first fall frost is December 13, giving you a growing season of approximately 306 days.

At an elevation of 2,752 feet, Brooks County receives approximately 64.5 inches of rainfall annually with predominantly loam soil. Summer highs average 104°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
Brooks County, TX (Zone 9b) Year-round
306 days
Last Spring Frost February 10
306 growing days
First Fall Frost December 13
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Brooks County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.2

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (102 days to spare)
Start indoors: Dec 8 Transplant: Dec 29 🌸 Bloom: Feb 23 – Aug 24
Recommended (50%) ✓ Fits season (89 days to spare)
Start indoors: Dec 30 Transplant: Jan 20 🌸 Bloom: Mar 17 – Sep 15
Safe Start (90%) ✓ Fits season (75 days to spare)
Start indoors: Jan 23 Transplant: Feb 13 🌸 Bloom: Apr 10 – Oct 9

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 Brooks County

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

Soil pH

Your soil pH (6.7–7.2) overlaps with Ageratum's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in Brooks 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 306-day season

Sow every 6.9 weeks. Last sowing by Sep 29 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 1,141 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 1.9" 0" ❄️ Dormant
Feb 4.3" 2.5" 1.8" 💧 Light watering
Mar 4.3" 3.6" 0.7" 💧 Light watering
Apr 4.3" 6.1" 0" ✅ Rainfall sufficient
May 4.3" 10.3" 0" ✅ Rainfall sufficient
Jun 4.3" 10.5" 0" ✅ Rainfall sufficient
Jul 4.3" 7.3" 0" ✅ Rainfall sufficient
Aug 4.3" 7.2" 0" ✅ Rainfall sufficient
Sep 4.3" 6" 0" ✅ Rainfall sufficient
Oct 4.3" 4.8" 0" ✅ Rainfall sufficient
Nov 4.3" 2.3" 2" 💧 Light watering
Dec 4.3" 1.8" 2.5" 🚿 Regular watering

Water needs are for active growing months only (Feb–Dec in Brooks 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 ~1,890 GDD — county provides 8,596 GDD Excellent fit

Ageratum Planting Timeline — Brooks County, TX

Ageratum Planting Calendar

Activity When Date Range
Start Indoors December 30 Dec 30 – Jan 13
Transplant Outdoors January 20 Jan 20 – Feb 3
Direct Sow January 20 Jan 20 – Feb 10
Bloom March 17 Mar 17 – Sep 15

· 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 Start Indoors
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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 9b

📆 Growing Season

306 days in Brooks County

Growing Tips for Ageratum in Brooks County

Direct sow Ageratum outdoors after February 10 in Brooks County when soil has warmed and frost danger has passed.

With summer highs reaching 104°F in Brooks 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 Brooks County, TX?

Brooks County is in Zone 9b with an average last frost of February 10. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Brooks County, TX?

Brooks County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 10 and first fall frost is December 13.

🌱

Your Brooks County Garden Planner — Free

A 22-page printable planner built for Brooks 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 Brooks 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.