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When to plant Ageratum in Linn County, MO

Linn County sits in USDA Zone 6a. Plant Ageratum between April 17 (after last frost on April 17) and May 8.

When to Plant Ageratum in Linn County, MO

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.

Linn County, Missouri is in USDA Zone 6a. The average last spring frost is April 17 and the first fall frost is October 20, giving you a growing season of approximately 186 days.

At an elevation of 880 feet, Linn County receives approximately 32.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Ageratum during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Linn County, MO (Zone 6a) Moderate season
186 days
Last Spring Frost April 17
186 growing days
First Fall Frost October 20

Linn County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.8

Drainage

Well Drained

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 1.7" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 4.3" 2.8" 1.5" 💧 Light watering
May 4.3" 3.5" 0.8" 💧 Light watering
Jun 4.3" 3.7" 0.6" 💧 Light watering
Jul 4.3" 3.5" 0.8" 💧 Light watering
Aug 4.3" 3.8" 0.5" 💧 Light watering
Sep 4.3" 2.9" 1.4" 💧 Light watering
Oct 4.3" 2.4" 1.9" 💧 Light watering
Nov 2.7" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Linn County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Ageratum Planting Timeline — Linn County, MO

Ageratum Planting Calendar

Activity When Date Range
Start Indoors February 27 Feb 27 – Mar 13
Transplant Outdoors April 17 Apr 17 – May 1
Direct Sow April 17 Apr 17 – May 8
Bloom June 12 Jun 12 – Sep 18

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Bloom
July Bloom
August Bloom
September Bloom
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 6a

📆 Growing Season

186 days in Linn County

Growing Tips for Linn County

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 Linn County, MO?

Linn County is in Zone 6a with an average last frost of April 17. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Linn County, MO?

Linn County, Missouri is in USDA Hardiness Zone 6a. The average last spring frost is April 17 and first fall frost is October 20.

When should I plant Ageratum in Linn County, MO?

In Linn County, MO, plant Ageratum after the last frost (around April 17) and before the first frost (around October 20). Best results when soil holds above 50°F.

What growing zone is Linn County, MO for Ageratum?

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

Can Ageratum grow in Linn County's climate?

Yes — Ageratum grows well in Linn County's temperate climate. Linn County averages a 186-day frost-free season, with last frost around April 17 and first frost around October 20.

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Your Linn County Garden Planner — Free

A 22-page printable planner built for Linn County (Zone 6a). 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 Linn County, MO. Local conditions may vary. Last updated: June 2026.

Sources & credits

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