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When to plant Ageratum in Crow Wing County, MN

The best window to plant Ageratum in Crow Wing County, is May 12–June 2, when soil warms to 50°F. Last frost typically hits May 5; first frost October 3.

When to Plant Ageratum in Crow Wing County, MN

Crow Wing County, Minnesota Zone 4a June

This month in Crow Wing County, Minnesota

Welcome to June in Zone 4a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 5
Avg. first frost October 3
Soil temp (4") 61°F
Watering Low
Pest pressure Moderate
Daylight 15.6 hrs
  1. Begin indoor sowing: ageratum

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

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.

Crow Wing County, Minnesota is in USDA Zone 4a. The average last spring frost is May 5 and the first fall frost is October 3, giving you a growing season of approximately 151 days.

At an elevation of 783 feet, Crow Wing County receives approximately 33.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 78°F, so choose short-season varieties of Ageratum to ensure they mature before fall.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Crow Wing County, MN (Zone 4a) Moderate season
151 days
Last Spring Frost May 5
151 growing days
First Fall Frost October 3

Crow Wing County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.7

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (19 days to spare)
Start indoors: Mar 4 Transplant: May 6 🌸 Bloom: Jul 1 – Sep 9
Recommended (50%) ✓ Fits season (18 days to spare)
Start indoors: Mar 10 Transplant: May 12 🌸 Bloom: Jul 7 – Sep 15
Safe Start (90%) ✓ Fits season (15 days to spare)
Start indoors: Mar 24 Transplant: May 26 🌸 Bloom: Jul 21 – Sep 29

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 Crow Wing County

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

Soil pH

Your soil pH (6.0–6.7) is within Ageratum's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.0%) — Ageratum will thrive.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

2
successive plantings in your 151-day season

Sow every 6.9 weeks. Last sowing by Jul 20 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 103 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 1.6" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 3.3" 0" ❄️ Dormant
May 4.3" 3.3" 1" 💧 Light watering
Jun 4.3" 3.9" 0.4" 💧 Light watering
Jul 4.3" 4.2" 0.1" 💧 Light watering
Aug 4.3" 3.3" 1" 💧 Light watering
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Crow Wing 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 ~574 GDD — county provides 1,283 GDD Excellent fit

Ageratum Planting Timeline — Crow Wing County, MN

Ageratum Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 – Mar 24
Transplant Outdoors May 12 May 12 – May 26
Direct Sow May 12 May 12 – Jun 2
Bloom July 7 Jul 7 – Sep 15

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors Direct Sow
June Direct Sow
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 4a

📆 Growing Season

151 days in Crow Wing County

Growing Tips for Ageratum in Crow Wing County

Direct sow Ageratum outdoors after May 05 in Crow Wing 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 Crow Wing County, MN?

Crow Wing County is in Zone 4a with an average last frost of May 5. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Crow Wing County, MN?

Crow Wing County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 5 and first fall frost is October 3.

When should I plant Ageratum in Crow Wing County, MN?

In Crow Wing County, MN, plant Ageratum after the last frost (around May 5) and before the first frost (around October 3). Best results when soil holds above 50°F.

What growing zone is Crow Wing County, MN for Ageratum?

Crow Wing County sits in USDA Zone 4a. Ageratum grows reliably in zones 3a through 11b, so it's a good fit here.

Can Ageratum grow in Crow Wing County's climate?

Yes — Ageratum grows well in Crow Wing County's temperate climate. Crow Wing County averages a 151-day frost-free season, with last frost around May 5 and first frost around October 3.

🌱

Your Crow Wing County Garden Planner — Free

A 22-page printable planner built for Crow Wing County (Zone 4a). 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 Crow Wing County, MN. Local conditions may vary. Last updated: June 2026.

Sources & credits

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