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When to plant Ageratum in Washington County County,

For Ageratum in Washington County County, the safe spring window opens around March 7 and closes around March 28. Last expected frost is March 21, first fall frost November 11, giving a 235-day growing season.

When to Plant Ageratum in Washington County, GA

Washington County, Georgia Zone 8b June

June to-do list for Washington County, Georgia

Your garden in Washington County, Georgia is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost March 21
Avg. first frost November 11
Soil temp (4") 83°F
Watering Low
Pest pressure High
Daylight 14.2 hrs
  1. Harvest ageratum as they ripen

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

To set up a strong July, finish these tasks
  • 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.

Washington County, Georgia is in USDA Zone 8b. The average last spring frost is March 21 and the first fall frost is November 11, giving you a growing season of approximately 235 days.

At an elevation of 277 feet, Washington County receives approximately 50.4 inches of rainfall annually with predominantly clay loam soil. Summer highs average 92°F, providing good warmth for Ageratum during the growing season. Clay soil retains moisture well for Ageratum, but amend with compost to improve drainage and prevent root rot. 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
Washington County, GA (Zone 8b) Long season
235 days
Last Spring Frost March 21
235 growing days
First Fall Frost November 11

Washington County Soil Profile

Soil Type

Clay Loam

Soil pH

5.5-6.3

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (41 days to spare)
Start indoors: Jan 28 Transplant: Feb 25 🌸 Bloom: Apr 22 – Sep 23
Recommended (50%) ✓ Fits season (39 days to spare)
Start indoors: Feb 7 Transplant: Mar 7 🌸 Bloom: May 2 – Oct 3
Safe Start (90%) ✓ Fits season (36 days to spare)
Start indoors: Feb 25 Transplant: Mar 25 🌸 Bloom: May 20 – Oct 21

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 Washington County

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

Soil pH

Your soil pH (5.5–6.3) is more acidic than Ageratum prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

4
successive plantings in your 235-day season

Sow every 6.9 weeks. Last sowing by Aug 28 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 208 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 4.3" 0" ❄️ Dormant
Feb 4.1" 0" ❄️ Dormant
Mar 4.3" 4.6" 0" ✅ Rainfall sufficient
Apr 4.3" 3.3" 1" 💧 Light watering
May 4.3" 3.6" 0.7" 💧 Light watering
Jun 4.3" 4.7" 0" ✅ Rainfall sufficient
Jul 4.3" 5.1" 0" ✅ Rainfall sufficient
Aug 4.3" 5.4" 0" ✅ Rainfall sufficient
Sep 4.3" 4.2" 0.1" 💧 Light watering
Oct 4.3" 3.6" 0.7" 💧 Light watering
Nov 4.3" 3.9" 0.4" 💧 Light watering
Dec 3.8" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Washington 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 ~1,282 GDD — county provides 4,465 GDD Excellent fit

Ageratum Planting Timeline — Washington County, GA

Ageratum Planting Calendar

Activity When Date Range
Start Indoors February 7 Feb 7 – Feb 21
Transplant Outdoors March 7 Mar 7 – Mar 21
Direct Sow March 7 Mar 7 – Mar 28
Bloom May 2 May 2 – Oct 3

· 8" apart · Rows 10" apart

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 8b

📆 Growing Season

235 days in Washington County

Growing Tips for Ageratum in Washington County

Direct sow Ageratum outdoors after March 21 in Washington County when soil has warmed and frost danger has passed.

With Washington County's clay soil (31% clay), work in 3-4 inches of compost before planting Ageratum. Avoid tilling when soil is wet to prevent compaction.

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 Washington County, GA?

Washington County is in Zone 8b with an average last frost of March 21. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Washington County, GA?

Washington County, Georgia is in USDA Hardiness Zone 8b. The average last spring frost is March 21 and first fall frost is November 11.

When should I plant Ageratum in Washington County, ?

In Washington County, , plant Ageratum after the last frost (around March 21) and before the first frost (around November 11). Best results when soil holds above 50°F.

What growing zone is Washington County, for Ageratum?

Washington County sits in USDA Zone 8b. Ageratum grows reliably in zones 3a through 11b, so it's a good fit here.

Can Ageratum grow in Washington County's climate?

Yes — Ageratum grows well in Washington County's temperate climate. Washington County averages a 235-day frost-free season, with last frost around March 21 and first frost around November 11.

🌱

Your Washington County Garden Planner — Free

A 22-page printable planner built for Washington 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 Washington County, GA. Local conditions may vary. Last updated: June 2026.

Sources & credits

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