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When to Plant Ageratum in Morris County, NJ

Morris County, New Jersey Zone 6b August

Your August game plan for Morris County, New Jersey

Here's what deserves your attention in Morris County, New Jersey this month. Everything below is tailored to Zone 6b and timed around your local frost dates.

Avg. last frost March 29
Avg. first frost November 12
Soil temp (4") 82°F
Watering Moderate
Pest pressure High
Daylight 13.6 hrs
  1. Start harvesting ageratum

    If you can't use it all right away, check the food-preservation section of your planner.

A few tasks this August that'll pay off in September
  • 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.

Morris County, New Jersey is in USDA Zone 6b. The average last spring frost is March 29 and the first fall frost is November 12, giving you a growing season of approximately 228 days.

At an elevation of 227 feet, Morris County receives approximately 40.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Ageratum during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Morris County, NJ (Zone 6b) Long season
228 days
Last Spring Frost March 29
228 growing days
First Fall Frost November 12

Morris 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 (67 days to spare)
Start indoors: Feb 4 Transplant: Mar 25 🌸 Bloom: May 20 – Sep 2
Recommended (50%) ✓ Fits season (67 days to spare)
Start indoors: Feb 8 Transplant: Mar 29 🌸 Bloom: May 24 – Sep 6
Safe Start (90%) ✓ Fits season (76 days to spare)
Start indoors: Feb 19 Transplant: Apr 9 🌸 Bloom: Jun 4 – Sep 17

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 Morris 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 Morris County is excellent for Ageratum — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.8%). Annual compost additions will help Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

4
successive plantings in your 228-day season

Sow every 6.9 weeks. Last sowing by Aug 29 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 504 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 3.1" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 4.3" 3.9" 0.4" 💧 Light watering
Apr 4.3" 3.1" 1.2" 💧 Light watering
May 4.3" 3.2" 1.1" 💧 Light watering
Jun 4.3" 4.1" 0.2" 💧 Light watering
Jul 4.3" 4.7" 0" ✅ Rainfall sufficient
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 3.5" 0.8" 💧 Light watering
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 4.3" 3" 1.3" 💧 Light watering
Dec 2.8" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Morris 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 ~1,232 GDD — county provides 4,161 GDD Excellent fit

Ageratum Planting Timeline — Morris County, NJ

Ageratum Planting Calendar

Activity When Date Range
Start Indoors February 8 Feb 8 – Feb 22
Transplant Outdoors March 29 Mar 29 – Apr 12
Direct Sow March 29 Mar 29 – Apr 19
Bloom May 24 May 24 – Sep 6

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March 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 6b

📆 Growing Season

228 days in Morris County

Growing Tips for Ageratum in Morris County

Direct sow Ageratum outdoors after March 29 in Morris 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 Morris County, NJ?

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

What planting zone is Morris County, NJ?

Morris County, New Jersey is in USDA Hardiness Zone 6b. The average last spring frost is March 29 and first fall frost is November 12.

🌱

Your Morris County Garden Planner — Free

A 22-page printable planner built for Morris 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 Morris County, NJ. 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.