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When to plant Ageratum in Shawnee County, KS

In Shawnee County, plant Ageratum in spring between April 14 and May 5, once soil temps hold above 50°F. Shawnee County's last frost averages April 14, so time plantings around the expected last-frost window for best survival. For a fall crop, sow between and — roughly 60–75 days before the first frost on October 22.

When to Plant Ageratum in Shawnee County, KS

Shawnee County, Kansas Zone 6b June

Your June planting checklist for Shawnee County, Kansas

We've pulled the most time-sensitive tasks for Shawnee County, Kansas this June and put them front and centre. Tackle them in order.

Avg. last frost April 14
Avg. first frost October 22
Soil temp (4") 75°F
Watering Low
Pest pressure High
Daylight 14.7 hrs
  1. Get ageratum seeds going inside

    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.

  2. It's harvest week for ageratum

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

July will be here before you know it — start on
  • 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.

Shawnee County, Kansas 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 923 feet, Shawnee County receives approximately 26.3 inches of rainfall annually with predominantly 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
Shawnee County, KS (Zone 6b) Moderate season
191 days
Last Spring Frost April 14
191 growing days
First Fall Frost October 22

Shawnee County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.3

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (27 days to spare)
Start indoors: Feb 19 Transplant: Apr 9 🌸 Bloom: Jun 4 – Sep 17
Recommended (50%) ✓ Fits season (30 days to spare)
Start indoors: Feb 24 Transplant: Apr 14 🌸 Bloom: Jun 9 – Sep 22
Safe Start (90%) ✓ Fits season (32 days to spare)
Start indoors: Mar 12 Transplant: Apr 30 🌸 Bloom: Jun 25 – Oct 8

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 Shawnee County

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

Soil pH

Your soil pH (6.2–7.3) overlaps with Ageratum's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Ageratum.

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 191-day season

Sow every 6.9 weeks. Last sowing by Aug 08 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,472 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 0.6" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 4.3" 2.4" 1.9" 💧 Light watering
May 4.3" 4.3" 0" ✅ Rainfall sufficient
Jun 4.3" 4.5" 0" ✅ Rainfall sufficient
Jul 4.3" 3" 1.3" 💧 Light watering
Aug 4.3" 3" 1.3" 💧 Light watering
Sep 4.3" 2.6" 1.7" 💧 Light watering
Oct 4.3" 1.8" 2.5" 🚿 Regular watering
Nov 0.9" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Shawnee 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 ~1,029 GDD — county provides 2,912 GDD Excellent fit

Ageratum Planting Timeline — Shawnee County, KS

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 · 2-3 times/week

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

191 days in Shawnee County

Growing Tips for Ageratum in Shawnee County

Direct sow Ageratum outdoors after April 14 in Shawnee 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 Shawnee County, KS?

Shawnee 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 Shawnee County, KS?

Shawnee County, Kansas 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 Shawnee County, KS?

In Shawnee County, KS, 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 Shawnee County, KS for Ageratum?

Shawnee 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 Shawnee County's climate?

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

🌱

Your Shawnee County Garden Planner — Free

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

Sources & credits

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