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When to Plant Ageratum in Lamb County, TX

Lamb County, Texas Zone 7a August

Your August game plan for Lamb County, Texas

August is a pivotal month for Lamb County, Texas gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 8
Avg. first frost October 27
Soil temp (4") 85°F
Watering Low
Pest pressure High
Daylight 13.3 hrs
  1. Pick ageratum

    If you can't use it all right away, check the food-preservation section of your planner.

Get ahead of September
  • 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.

Lamb County, Texas is in USDA Zone 7a. The average last spring frost is April 8 and the first fall frost is October 27, giving you a growing season of approximately 202 days.

At an elevation of 1,440 feet, Lamb County receives approximately 56.5 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. 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
Lamb County, TX (Zone 7a) Long season
202 days
Last Spring Frost April 8
202 growing days
First Fall Frost October 27

Lamb County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.5-8.4

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (30 days to spare)
Start indoors: Feb 20 Transplant: Apr 3 🌸 Bloom: May 29 – Sep 18
Recommended (50%) ✓ Fits season (34 days to spare)
Start indoors: Feb 25 Transplant: Apr 8 🌸 Bloom: Jun 3 – Sep 23
Safe Start (90%) ✓ Fits season (34 days to spare)
Start indoors: Mar 16 Transplant: Apr 27 🌸 Bloom: Jun 22 – Oct 12

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 Lamb County

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

Soil pH

Your soil pH (7.5–8.4) is more alkaline than Ageratum prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Lamb 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 (0.9%). Add 2-3 inches of compost before planting Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

3
successive plantings in your 202-day season

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

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 3.9" 0" ❄️ Dormant
Feb 2.8" 0" ❄️ Dormant
Mar 3.5" 0" ❄️ Dormant
Apr 4.3" 2" 2.3" 🚿 Regular watering
May 4.3" 1.2" 3.1" 🚿 Regular watering
Jun 4.3" 2" 2.3" 🚿 Regular watering
Jul 4.3" 8.9" 0" ✅ Rainfall sufficient
Aug 4.3" 11.2" 0" ✅ Rainfall sufficient
Sep 4.3" 8.8" 0" ✅ Rainfall sufficient
Oct 4.3" 5.2" 0" ✅ Rainfall sufficient
Nov 3.4" 0" ❄️ Dormant
Dec 3.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Lamb 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 4,444 GDD Excellent fit

Ageratum Planting Timeline — Lamb County, TX

Ageratum Planting Calendar

Activity When Date Range
Start Indoors February 25 Feb 25 – Mar 11
Transplant Outdoors April 8 Apr 8 – Apr 22
Direct Sow April 8 Apr 8 – Apr 29
Bloom June 3 Jun 3 – Sep 23

· 8" apart · Rows 10" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 7a

📆 Growing Season

202 days in Lamb County

Growing Tips for Ageratum in Lamb County

Direct sow Ageratum outdoors after April 08 in Lamb County when soil has warmed and frost danger has passed.

Sandy soil in Lamb 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 Lamb 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 Lamb County, TX?

Lamb County is in Zone 7a with an average last frost of April 8. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lamb County, TX?

Lamb County, Texas is in USDA Hardiness Zone 7a. The average last spring frost is April 8 and first fall frost is October 27.

🌱

Your Lamb County Garden Planner — Free

A 22-page printable planner built for Lamb County (Zone 7a). 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 Lamb County, TX. Local conditions may vary. Last updated: August 2026.

Sources & credits

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