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When to Plant Ageratum in Clinton County, PA

Clinton County, Pennsylvania Zone 6b June

Clinton County, Pennsylvania gardeners: here's your June plan

A quick June briefing for Clinton County, Pennsylvania gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 29
Avg. first frost October 18
Soil temp (4") 70°F
Watering Low
Pest pressure High
Daylight 15 hrs
  1. Fire up the seed-starting tray: ageratum

    Label every cell. You will absolutely forget which is which otherwise.

  2. Collect ageratum at their peak

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

July prep starts now
  • 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.

Clinton County, Pennsylvania is in USDA Zone 6b. The average last spring frost is April 29 and the first fall frost is October 18, giving you a growing season of approximately 172 days.

At an elevation of 9 feet, Clinton County receives approximately 40.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Ageratum to ensure they mature before fall.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Clinton County, PA (Zone 6b) Moderate season
172 days
Last Spring Frost April 29
172 growing days
First Fall Frost October 18

Clinton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.5

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (7 days to spare)
Start indoors: Mar 8 Transplant: Apr 26 🌸 Bloom: Jun 21 – Oct 4
Recommended (50%) ✓ Fits season (11 days to spare)
Start indoors: Mar 11 Transplant: Apr 29 🌸 Bloom: Jun 24 – Oct 7
Safe Start (90%) ✓ Fits season (7 days to spare)
Start indoors: Mar 31 Transplant: May 19 🌸 Bloom: Jul 14 – Oct 27

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 Clinton County

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

Soil pH

Your soil pH (5.1–6.5) is more acidic than Ageratum prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.7%). Annual compost additions will help Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

3
successive plantings in your 172-day season

Sow every 6.9 weeks. Last sowing by Aug 04 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 17 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" 0" ❄️ Dormant
Feb 2.3" 0" ❄️ Dormant
Mar 3.4" 0" ❄️ Dormant
Apr 4.3" 3.3" 1" 💧 Light watering
May 4.3" 3.3" 1" 💧 Light watering
Jun 4.3" 3.8" 0.5" 💧 Light watering
Jul 4.3" 4.2" 0.1" 💧 Light watering
Aug 4.3" 3.6" 0.7" 💧 Light watering
Sep 4.3" 3.8" 0.5" 💧 Light watering
Oct 4.3" 3.5" 0.8" 💧 Light watering
Nov 2.9" 0" ❄️ Dormant
Dec 3.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Clinton 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 ~827 GDD — county provides 2,107 GDD Excellent fit

Ageratum Planting Timeline — Clinton County, PA

Ageratum Planting Calendar

Activity When Date Range
Start Indoors March 11 Mar 11 – Mar 25
Transplant Outdoors April 29 Apr 29 – May 13
Direct Sow April 29 Apr 29 – May 20
Bloom June 24 Jun 24 – Oct 7

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors 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 · Only during dry spells

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

172 days in Clinton County

Growing Tips for Ageratum in Clinton County

Direct sow Ageratum outdoors after April 29 in Clinton 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 Clinton County, PA?

Clinton County is in Zone 6b with an average last frost of April 29. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clinton County, PA?

Clinton County, Pennsylvania is in USDA Hardiness Zone 6b. The average last spring frost is April 29 and first fall frost is October 18.

🌱

Your Clinton County Garden Planner — Free

A 22-page printable planner built for Clinton County (Zone 6b). 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 Clinton County, PA. 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.