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When to Plant Ageratum in Hardeman County, TN

Hardeman County, Tennessee Zone 7b June

Hardeman County, Tennessee gardeners: here's your June plan

Here's what deserves your attention in Hardeman County, Tennessee this month. Everything below is tailored to Zone 7b and timed around your local frost dates.

Avg. last frost March 30
Avg. first frost October 30
Soil temp (4") 69°F
Watering Moderate
Pest pressure High
Daylight 14.4 hrs
  1. Basket week: ageratum

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  • 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.

Hardeman County, Tennessee is in USDA Zone 7b. The average last spring frost is March 30 and the first fall frost is October 30, giving you a growing season of approximately 214 days.

At an elevation of 3,185 feet, Hardeman County receives approximately 48.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 92°F, providing good warmth for Ageratum during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Hardeman County, TN (Zone 7b) Long season
214 days
Last Spring Frost March 30
214 growing days
First Fall Frost October 30

Hardeman County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.5

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (33 days to spare)
Start indoors: Feb 10 Transplant: Mar 24 🌸 Bloom: May 19 – Sep 22
Recommended (50%) ✓ Fits season (32 days to spare)
Start indoors: Feb 16 Transplant: Mar 30 🌸 Bloom: May 25 – Sep 28
Safe Start (90%) ✓ Fits season (29 days to spare)
Start indoors: Mar 5 Transplant: Apr 16 🌸 Bloom: Jun 11 – Oct 15

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 Hardeman County

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

Soil pH

Your soil pH (5.2–6.5) is more acidic than Ageratum prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

4
successive plantings in your 214-day season

Sow every 6.9 weeks. Last sowing by Aug 16 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 88 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 3.5" 0" ❄️ Dormant
Feb 4.1" 0" ❄️ Dormant
Mar 4.3" 5.2" 0" ✅ Rainfall sufficient
Apr 4.3" 3.7" 0.6" 💧 Light watering
May 4.3" 3.7" 0.6" 💧 Light watering
Jun 4.3" 3.7" 0.6" 💧 Light watering
Jul 4.3" 5" 0" ✅ Rainfall sufficient
Aug 4.3" 4.6" 0" ✅ Rainfall sufficient
Sep 4.3" 4.1" 0.2" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 3.7" 0" ❄️ Dormant
Dec 4.4" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Oct in Hardeman 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 4,066 GDD Excellent fit

Ageratum Planting Timeline — Hardeman County, TN

Ageratum Planting Calendar

Activity When Date Range
Start Indoors February 16 Feb 16 – Mar 2
Transplant Outdoors March 30 Mar 30 – Apr 13
Direct Sow March 30 Mar 30 – Apr 20
Bloom May 25 May 25 – Sep 28

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors Transplant Outdoors Direct Sow
April Transplant Outdoors Direct Sow
May Bloom
June Bloom
July Bloom
August Bloom
September Bloom
October
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 7b

📆 Growing Season

214 days in Hardeman County

Growing Tips for Ageratum in Hardeman County

Direct sow Ageratum outdoors after March 30 in Hardeman County when soil has warmed and frost danger has passed.

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 Hardeman County, TN?

Hardeman County is in Zone 7b with an average last frost of March 30. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hardeman County, TN?

Hardeman County, Tennessee is in USDA Hardiness Zone 7b. The average last spring frost is March 30 and first fall frost is October 30.

🌱

Your Hardeman County Garden Planner — Free

A 22-page printable planner built for Hardeman 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.

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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 Hardeman County, TN. 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.