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When to Plant Ageratum in Terrell County, TX

Terrell County, Texas Zone 8b June

What to do in June

If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.

Avg. last frost March 2
Avg. first frost November 27
Soil temp (4") 71°F
Watering High
Pest pressure High
Daylight 13.9 hrs
  1. Pick ageratum

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

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.

Terrell County, Texas is in USDA Zone 8b. The average last spring frost is March 2 and the first fall frost is November 27, giving you a growing season of approximately 270 days.

At an elevation of 3,434 feet, Terrell County receives approximately 45.8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96°F, so Ageratum may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Ageratum will need more frequent watering and organic matter to retain nutrients.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Terrell County, TX (Zone 8b) Year-round
270 days
Last Spring Frost March 2
270 growing days
First Fall Frost November 27

Terrell County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.3-8.4

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (80 days to spare)
Start indoors: Jan 8 Transplant: Feb 5 🌸 Bloom: Apr 2 – Sep 3
Recommended (50%) ✓ Fits season (74 days to spare)
Start indoors: Jan 19 Transplant: Feb 16 🌸 Bloom: Apr 13 – Sep 14
Safe Start (90%) ✓ Fits season (67 days to spare)
Start indoors: Feb 8 Transplant: Mar 8 🌸 Bloom: May 3 – Oct 4

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 Terrell County

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

Soil pH

Your soil pH (7.3–8.4) is more alkaline than Ageratum prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Terrell County warms quickly in spring but drains fast. Ageratum will need more frequent watering and regular compost additions to retain nutrients.

Organic Matter

Organic matter is low (1.0%). Add 2-3 inches of compost before planting Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

5
successive plantings in your 270-day season

Sow every 6.9 weeks. Last sowing by Sep 13 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 829 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 3" 0" ❄️ Dormant
Feb 2.4" 0" ❄️ Dormant
Mar 4.3" 2.8" 1.5" 💧 Light watering
Apr 4.3" 1.7" 2.6" 🚿 Regular watering
May 4.3" 1.1" 3.2" 🚿 Regular watering
Jun 4.3" 1.7" 2.6" 🚿 Regular watering
Jul 4.3" 7.7" 0" ✅ Rainfall sufficient
Aug 4.3" 9" 0" ✅ Rainfall sufficient
Sep 4.3" 5.6" 0" ✅ Rainfall sufficient
Oct 4.3" 4.9" 0" ✅ Rainfall sufficient
Nov 4.3" 2.5" 1.8" 💧 Light watering
Dec 3.4" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Terrell 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 ~1,485 GDD — county provides 5,940 GDD Excellent fit

Ageratum Planting Timeline — Terrell County, TX

Ageratum Planting Calendar

Activity When Date Range
Start Indoors January 19 Jan 19 – Feb 2
Transplant Outdoors February 16 Feb 16 – Mar 2
Direct Sow February 16 Feb 16 – Mar 9
Bloom April 13 Apr 13 – Sep 14

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors Transplant Outdoors Direct Sow
March Transplant Outdoors Direct Sow
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 · 1-2 times/week

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 8b

📆 Growing Season

270 days in Terrell County

Growing Tips for Ageratum in Terrell County

Direct sow Ageratum outdoors after March 02 in Terrell County when soil has warmed and frost danger has passed.

Sandy soil in Terrell County dries quickly — mulch Ageratum with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 96°F in Terrell 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 Terrell County, TX?

Terrell County is in Zone 8b with an average last frost of March 2. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Terrell County, TX?

Terrell County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 2 and first fall frost is November 27.

🌱

Your Terrell County Garden Planner — Free

A 22-page printable planner built for Terrell 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 Terrell 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.