Blog

When to plant Ageratum in Union County, GA

Plant Ageratum in Union County, when soil hits 50°F — usually April 11. Continue planting through May 2 for the spring crop.

When to Plant Ageratum in Union County, GA

Union County, Georgia Zone 7b August

Your August gardening checklist

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

Avg. last frost April 11
Avg. first frost October 23
Soil temp (4") 88°F
Watering Low
Pest pressure High
Daylight 13.3 hrs
  1. Start harvesting ageratum

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

To set up a strong September, finish these tasks
  • First harvests: ageratum

Instant PDF download. No spam, unsubscribe any time.

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.

Union County, Georgia is in USDA Zone 7b. The average last spring frost is April 11 and the first fall frost is October 23, giving you a growing season of approximately 195 days.

At an elevation of 175 feet, Union County receives approximately 61.4 inches of rainfall annually with predominantly clay loam soil. Summer highs average 93°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
Union County, GA (Zone 7b) Moderate season
195 days
Last Spring Frost April 11
195 growing days
First Fall Frost October 23

Union County Soil Profile

Soil Type

Clay Loam

Soil pH

5.8-6.2

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (18 days to spare)
Start indoors: Feb 17 Transplant: Mar 31 🌸 Bloom: May 26 – Sep 29
Recommended (50%) ✓ Fits season (13 days to spare)
Start indoors: Feb 28 Transplant: Apr 11 🌸 Bloom: Jun 6 – Oct 10
Safe Start (90%) ✓ Fits season (18 days to spare)
Start indoors: Mar 22 Transplant: May 3 🌸 Bloom: Jun 28 – Nov 1

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 Union County

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

Soil pH

Your soil pH (5.8–6.2) overlaps with Ageratum's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

3
successive plantings in your 195-day season

Sow every 6.9 weeks. Last sowing by Aug 09 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
1.3″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 6" 0" ❄️ Dormant
Feb 4.6" 0" ❄️ Dormant
Mar 5.8" 0" ❄️ Dormant
Apr 4.3" 4.5" 0" ✅ Rainfall sufficient
May 4.3" 5.3" 0" ✅ Rainfall sufficient
Jun 4.3" 5.1" 0" ✅ Rainfall sufficient
Jul 4.3" 5.7" 0" ✅ Rainfall sufficient
Aug 4.3" 6.2" 0" ✅ Rainfall sufficient
Sep 4.3" 4.8" 0" ✅ Rainfall sufficient
Oct 4.3" 3.6" 0.7" 💧 Light watering
Nov 4.2" 0" ❄️ Dormant
Dec 5.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Union 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 ~1,333 GDD — county provides 3,851 GDD Excellent fit

Ageratum Planting Timeline — Union County, GA

Ageratum Planting Calendar

Activity When Date Range
Start Indoors February 28 Feb 28 – Mar 14
Transplant Outdoors April 11 Apr 11 – Apr 25
Direct Sow April 11 Apr 11 – May 2
Bloom June 6 Jun 6 – Oct 10

· 8" apart · Rows 10" apart

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 7b

📆 Growing Season

195 days in Union County

Growing Tips for Ageratum in Union County

Direct sow Ageratum outdoors after April 11 in Union County when soil has warmed and frost danger has passed.

With Union County's clay soil (28% 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 Union County, GA?

Union County is in Zone 7b with an average last frost of April 11. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Union County, GA?

Union County, Georgia is in USDA Hardiness Zone 7b. The average last spring frost is April 11 and first fall frost is October 23.

When should I plant Ageratum in Union County, GA?

In Union County, GA, plant Ageratum after the last frost (around April 11) and before the first frost (around October 23). Best results when soil holds above 50°F.

What growing zone is Union County, GA for Ageratum?

Union County sits in USDA Zone 7b. Ageratum grows reliably in zones 3a through 11b, so it's a good fit here.

Can Ageratum grow in Union County's climate?

Yes — Ageratum grows well in Union County's temperate climate. Union County averages a 195-day frost-free season, with last frost around April 11 and first frost around October 23.

🌱

Your Union County Garden Planner — Free

A 22-page printable planner built for Union County (Zone 7b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Union County, GA. 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.