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When to plant Ageratum in Brown County County,

Plant Ageratum in Brown County County, when soil hits 50°F — usually May 7. Continue planting through May 28 for the spring crop.

When to Plant Ageratum in Brown County, MN

Brown County, Minnesota Zone 5a June

Your June gardening checklist

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Brown County, Minnesota.

Avg. last frost April 30
Avg. first frost October 7
Soil temp (4") 65°F
Watering Low
Pest pressure High
Daylight 15.3 hrs
  1. Begin indoor sowing: ageratum

    These need a head start before your last frost (April 30). Sow into cells now so you're ready to transplant in a few weeks.

To set up a strong July, finish these tasks
  • 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.

Brown County, Minnesota is in USDA Zone 5a. The average last spring frost is April 30 and the first fall frost is October 7, giving you a growing season of approximately 160 days.

At an elevation of 1,199 feet, Brown County receives approximately 31.8 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
Brown County, MN (Zone 5a) Moderate season
160 days
Last Spring Frost April 30
160 growing days
First Fall Frost October 7

Brown County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (11 days to spare)
Start indoors: Mar 6 Transplant: May 1 🌸 Bloom: Jun 26 – Sep 18
Recommended (50%) ✓ Fits season (13 days to spare)
Start indoors: Mar 12 Transplant: May 7 🌸 Bloom: Jul 2 – Sep 24
Safe Start (90%) ✓ Fits season (12 days to spare)
Start indoors: Mar 27 Transplant: May 22 🌸 Bloom: Jul 17 – Oct 9

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 Brown County

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

Soil pH

Your soil pH (6.1–7.0) is within Ageratum's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) — Ageratum will thrive.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

3
successive plantings in your 160-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
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 282 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.2" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 4.3" 3.4" 0.9" 💧 Light watering
May 4.3" 3.6" 0.7" 💧 Light watering
Jun 4.3" 4" 0.3" 💧 Light watering
Jul 4.3" 3.6" 0.7" 💧 Light watering
Aug 4.3" 3.3" 1" 💧 Light watering
Sep 4.3" 2.8" 1.5" 💧 Light watering
Oct 4.3" 2" 2.3" 🚿 Regular watering
Nov 2.2" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Brown 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 1,960 GDD Excellent fit

Ageratum Planting Timeline — Brown County, MN

Ageratum Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 – Mar 26
Transplant Outdoors May 7 May 7 – May 21
Direct Sow May 7 May 7 – May 28
Bloom July 2 Jul 2 – Sep 24

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors Direct Sow
June
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 5a

📆 Growing Season

160 days in Brown County

Growing Tips for Ageratum in Brown County

Direct sow Ageratum outdoors after April 30 in Brown 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 Brown County, MN?

Brown County is in Zone 5a with an average last frost of April 30. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Brown County, MN?

Brown County, Minnesota is in USDA Hardiness Zone 5a. The average last spring frost is April 30 and first fall frost is October 7.

When should I plant Ageratum in Brown County, ?

In Brown County, , plant Ageratum after the last frost (around April 30) and before the first frost (around October 7). Best results when soil holds above 50°F.

What growing zone is Brown County, for Ageratum?

Brown County sits in USDA Zone 5a. Ageratum grows reliably in zones 3a through 11b, so it's a good fit here.

Can Ageratum grow in Brown County's climate?

Yes — Ageratum grows well in Brown County's temperate climate. Brown County averages a 160-day frost-free season, with last frost around April 30 and first frost around October 7.

🌱

Your Brown County Garden Planner — Free

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

Sources & credits

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