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When to Plant Ageratum in Orange County, VT

Orange County, Vermont Zone 5a June

Top priorities for Orange County, Vermont gardeners in June

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

Avg. last frost May 12
Avg. first frost October 7
Soil temp (4") 64°F
Watering Moderate
Pest pressure High
Daylight 15.3 hrs
  1. Fire up the seed-starting tray: ageratum

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

July will be here before you know it — start on
  • 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.

Orange County, Vermont is in USDA Zone 5a. The average last spring frost is May 12 and the first fall frost is October 7, giving you a growing season of approximately 148 days.

At an elevation of 604 feet, Orange County receives approximately 38.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Ageratum to ensure they mature before fall.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Orange County, VT (Zone 5a) Short season
148 days
Last Spring Frost May 12
148 growing days
First Fall Frost October 7

Orange County Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.7

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (3 days to spare)
Start indoors: Mar 18 Transplant: May 13 🌸 Bloom: Jul 8 – Sep 30
Recommended (50%) ✓ Fits season (1 days to spare)
Start indoors: Mar 24 Transplant: May 19 🌸 Bloom: Jul 14 – Oct 6
Safe Start (90%) ✓ Fits season (1 days to spare)
Start indoors: Apr 6 Transplant: Jun 1 🌸 Bloom: Jul 27 – Oct 19

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 Orange County

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

Soil pH

Your soil pH (5.1–6.7) is more acidic than Ageratum prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Ageratum.

Organic Matter

Organic matter is moderate (3.5%). Annual compost additions will help Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

2
successive plantings in your 148-day season

Sow every 6.9 weeks. Last sowing by Jul 24 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/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 2.9" 0" ❄️ Dormant
Feb 2.3" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 3.7" 0" ❄️ Dormant
May 4.3" 4" 0.3" 💧 Light watering
Jun 4.3" 3.3" 1" 💧 Light watering
Jul 4.3" 3.8" 0.5" 💧 Light watering
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 3.1" 1.2" 💧 Light watering
Oct 4.3" 3.5" 0.8" 💧 Light watering
Nov 3.3" 0" ❄️ Dormant
Dec 2.5" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Orange 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 ~776 GDD — county provides 1,702 GDD Excellent fit

Ageratum Planting Timeline — Orange County, VT

Ageratum Planting Calendar

Activity When Date Range
Start Indoors March 24 Mar 24 – Apr 7
Transplant Outdoors May 19 May 19 – Jun 2
Direct Sow May 19 May 19 – Jun 9
Bloom July 14 Jul 14 – Oct 6

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
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: too_acidic

🗺️ USDA Zone

Zone 5a

📆 Growing Season

148 days in Orange County

Growing Tips for Ageratum in Orange County

Direct sow Ageratum outdoors after May 12 in Orange 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 Orange County, VT?

Orange County is in Zone 5a with an average last frost of May 12. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Orange County, VT?

Orange County, Vermont is in USDA Hardiness Zone 5a. The average last spring frost is May 12 and first fall frost is October 7.

🌱

Your Orange County Garden Planner — Free

A 22-page printable planner built for Orange County (Zone 5a). 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 Orange County, VT. Local conditions may vary. Last updated: June 2026.

Sources & credits

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