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When to plant Ageratum in Clark County County,

Clark County County's climate puts the Ageratum spring window between April 10 and May 1. most warm-season crops establish quickly once soil holds above 60°F.

When to Plant Ageratum in Clark County, IN

Clark County, Indiana Zone 7a June

June in Clark County, Indiana — your action list

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

Avg. last frost April 10
Avg. first frost October 22
Soil temp (4") 72°F
Watering Low
Pest pressure High
Daylight 14.7 hrs
  1. It's harvest week for ageratum

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

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.

Clark County, Indiana is in USDA Zone 7a. The average last spring frost is April 10 and the first fall frost is October 22, giving you a growing season of approximately 195 days.

At an elevation of 1,265 feet, Clark County receives approximately 36.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Ageratum during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Clark County, IN (Zone 7a) Moderate season
195 days
Last Spring Frost April 10
195 growing days
First Fall Frost October 22
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Clark County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.7

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (28 days to spare)
Start indoors: Feb 21 Transplant: Apr 4 🌸 Bloom: May 30 – Sep 19
Recommended (50%) ✓ Fits season (27 days to spare)
Start indoors: Feb 27 Transplant: Apr 10 🌸 Bloom: Jun 5 – Sep 25
Safe Start (90%) ✓ Fits season (24 days to spare)
Start indoors: Mar 19 Transplant: Apr 30 🌸 Bloom: Jun 25 – 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 Clark County

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

Soil pH

Your soil pH (5.8–6.7) overlaps with Ageratum's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — Ageratum will thrive.

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 08 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 356 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 1.4" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 4.3" 3.8" 0.5" 💧 Light watering
May 4.3" 4.5" 0" ✅ Rainfall sufficient
Jun 4.3" 4.5" 0" ✅ Rainfall sufficient
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 3.5" 0.8" 💧 Light watering
Sep 4.3" 2.8" 1.5" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 3" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Clark 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 ~1,029 GDD — county provides 2,973 GDD Excellent fit

Ageratum Planting Timeline — Clark County, IN

Ageratum Planting Calendar

Activity When Date Range
Start Indoors February 27 Feb 27 – Mar 13
Transplant Outdoors April 10 Apr 10 – Apr 24
Direct Sow April 10 Apr 10 – May 1
Bloom June 5 Jun 5 – Sep 25

· 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
November
December
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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: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

195 days in Clark County

Growing Tips for Ageratum in Clark County

Direct sow Ageratum outdoors after April 10 in Clark 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 Clark County, IN?

Clark County is in Zone 7a with an average last frost of April 10. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clark County, IN?

Clark County, Indiana is in USDA Hardiness Zone 7a. The average last spring frost is April 10 and first fall frost is October 22.

When should I plant Ageratum in Clark County County, ?

In Clark County County, , plant Ageratum after the last frost (around April 10) and before the first frost (around October 22). Best results when soil holds above 50°F.

What growing zone is Clark County County, for Ageratum?

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

Can Ageratum grow in Clark County County's climate?

Yes — Ageratum grows well in Clark County County's temperate climate. Clark County County averages a 195-day frost-free season, with last frost around April 10 and first frost around October 22.

🌱

Your Clark County Garden Planner — Free

A 22-page printable planner built for Clark 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 Clark County, IN. 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.