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When to plant Ageratum in Mode, IL

Mode's spring Ageratum window runs April 14 through May 5. time plantings around the expected last-frost window for best survival.

When to Plant Ageratum in Mode, IL

Shelby County, Illinois Zone 6b June

Your June planting checklist for Shelby County, Illinois

Each item below is timed to Shelby County, Illinois's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 14
Avg. first frost October 17
Soil temp (4") 70°F
Watering Low
Pest pressure High
Daylight 14.8 hrs
  1. Indoor seed-starting week for ageratum

    Your window is short. These crops want several weeks of indoor growth before they go outside.

  2. Basket week: ageratum

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

A few tasks this June that'll pay off in 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.

Mode, Illinois is in USDA Zone 6b. The average last spring frost is April 14 and the first fall frost is October 17, giving you a growing season of approximately 186 days.

At an elevation of 807 feet, Shelby County receives approximately 41 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Ageratum during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Mode, IL (Zone 6b) Moderate season
186 days
Last Spring Frost April 14
186 growing days
First Fall Frost October 17

Mode Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (27 days to spare)
Start indoors: Feb 18 Transplant: Apr 8 🌸 Bloom: Jun 3 – Sep 16
Recommended (50%) ✓ Fits season (25 days to spare)
Start indoors: Feb 24 Transplant: Apr 14 🌸 Bloom: Jun 9 – Sep 22
Safe Start (90%) ✓ Fits season (31 days to spare)
Start indoors: Mar 6 Transplant: Apr 24 🌸 Bloom: Jun 19 – Oct 2

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 Mode

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

Soil pH

Your soil pH (6.2–7.0) is within Ageratum's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.7%) — Ageratum will thrive.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

3
successive plantings in your 186-day season

Sow every 6.9 weeks. Last sowing by Aug 03 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 123 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 1.9" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 4.3" 4.4" 0" ✅ Rainfall sufficient
May 4.3" 4.4" 0" ✅ Rainfall sufficient
Jun 4.3" 5.3" 0" ✅ Rainfall sufficient
Jul 4.3" 4" 0.3" 💧 Light watering
Aug 4.3" 4" 0.3" 💧 Light watering
Sep 4.3" 4.2" 0.1" 💧 Light watering
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 3" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Shelby 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 ~979 GDD — county provides 2,697 GDD Excellent fit

Ageratum Planting Timeline — Mode, IL

Ageratum Planting Calendar

Activity When Date Range
Start Indoors February 24 Feb 24 – Mar 10
Transplant Outdoors April 14 Apr 14 – Apr 28
Direct Sow April 14 Apr 14 – May 5
Bloom June 9 Jun 9 – Sep 22

· 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

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: ideal

🗺️ USDA Zone

Zone 6b

📆 Growing Season

186 days in Shelby County

Growing Tips for Ageratum in Mode

Direct sow Ageratum outdoors after April 14 in Shelby 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 →

When should I plant Ageratum in Mode, IL?

In Mode, IL, plant Ageratum after the last frost (around April 14) and before the first frost (around October 17). Best results when soil holds above 50°F.

What growing zone is Mode, IL for Ageratum?

Mode sits in USDA Zone 6b. Ageratum grows reliably in zones 3a through 11b, so it's a good fit here.

Can Ageratum grow in Mode's climate?

Yes — Ageratum grows well in Mode's temperate climate. Mode averages a 186-day frost-free season, with last frost around April 14 and first frost around October 17.

🌱

Your Shelby County Garden Planner — Free

A 22-page printable planner built for Shelby 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 Shelby County, IL. Local conditions may vary. Last updated: June 2026.