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When to plant Ageratum in Cass County, MO

The best window to plant Ageratum in Cass County, is April 14–May 5, when soil warms to 50°F. Last frost typically hits April 14; first frost October 22.

When to Plant Ageratum in Cass 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.

Cass County, Missouri is in USDA Zone 6b. The average last spring frost is April 14 and the first fall frost is October 22, giving you a growing season of approximately 191 days.

At an elevation of 910 feet, Cass County receives approximately 37 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Ageratum during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Cass County, MO (Zone 6b) Moderate season
191 days
Last Spring Frost April 14
191 growing days
First Fall Frost October 22

Cass County Soil Profile

Soil Type

Silt Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Ageratum Planting Timeline — Cass County, MO

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

Moderate — regular watering

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 6b

📆 Growing Season

191 days in Cass County

Growing Tips for Cass 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 Cass County, MO?

Cass County is in Zone 6b with an average last frost of April 14. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cass County, MO?

Cass County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 14 and first fall frost is October 22.

When should I plant Ageratum in Cass County, MO?

In Cass County, MO, plant Ageratum after the last frost (around April 14) and before the first frost (around October 22). Best results when soil holds above 50°F.

What growing zone is Cass County, MO for Ageratum?

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

Can Ageratum grow in Cass County's climate?

Yes — Ageratum grows well in Cass County's temperate climate. Cass County averages a 191-day frost-free season, with last frost around April 14 and first frost around October 22.

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Your Cass County Garden Planner — Free

A 22-page printable planner built for Cass 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 Cass County, MO. Local conditions may vary. Last updated: August 2026.

Sources & credits

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