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When to plant Ageratum in Allen County, KS

In Allen County, plant Ageratum in spring between April 8 and April 29, once soil temps hold above 50°F. Allen County's last frost averages April 8, 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 25.

When to Plant Ageratum in Allen County, KS

Allen County, Kansas Zone 6b June

This month in Allen County, Kansas

Your Allen County, Kansas garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost April 8
Avg. first frost October 25
Soil temp (4") 76°F
Watering Low
Pest pressure High
Daylight 14.6 hrs
  1. It's harvest week for ageratum

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

A few tasks this June that'll pay off in July
  • 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.

Allen County, Kansas is in USDA Zone 6b. The average last spring frost is April 8 and the first fall frost is October 25, giving you a growing season of approximately 200 days.

At an elevation of 578 feet, Allen County receives approximately 26.6 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Ageratum during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Allen County, KS (Zone 6b) Long season
200 days
Last Spring Frost April 8
200 growing days
First Fall Frost October 25

Allen County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.8

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (38 days to spare)
Start indoors: Feb 13 Transplant: Apr 3 🌸 Bloom: May 29 – Sep 11
Recommended (50%) ✓ Fits season (39 days to spare)
Start indoors: Feb 18 Transplant: Apr 8 🌸 Bloom: Jun 3 – Sep 16
Safe Start (90%) ✓ Fits season (44 days to spare)
Start indoors: Mar 1 Transplant: Apr 19 🌸 Bloom: Jun 14 – Sep 27

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 Allen County

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

Soil pH

Your soil pH (6.5–7.8) is more alkaline than Ageratum prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.1%) — Ageratum will thrive.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

3
successive plantings in your 200-day season

Sow every 6.9 weeks. Last sowing by Aug 11 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 943 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 0.7" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 4.3" 2.7" 1.6" 💧 Light watering
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 4.9" 0" ✅ Rainfall sufficient
Jul 4.3" 3.6" 0.7" 💧 Light watering
Aug 4.3" 2.7" 1.6" 💧 Light watering
Sep 4.3" 2.2" 2.1" 💧 Light watering
Oct 4.3" 1.6" 2.7" 🚿 Regular watering
Nov 0.8" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Allen 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 ~1,080 GDD — county provides 3,200 GDD Excellent fit

Ageratum Planting Timeline — Allen County, KS

Ageratum Planting Calendar

Activity When Date Range
Start Indoors February 18 Feb 18 – Mar 4
Transplant Outdoors April 8 Apr 8 – Apr 22
Direct Sow April 8 Apr 8 – Apr 29
Bloom June 3 Jun 3 – Sep 16

· 8" apart · Rows 10" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

200 days in Allen County

Growing Tips for Ageratum in Allen County

Direct sow Ageratum outdoors after April 08 in Allen 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 Allen County, KS?

Allen County is in Zone 6b with an average last frost of April 8. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Allen County, KS?

Allen County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 8 and first fall frost is October 25.

When should I plant Ageratum in Allen County, KS?

In Allen County, KS, plant Ageratum after the last frost (around April 8) and before the first frost (around October 25). Best results when soil holds above 50°F.

What growing zone is Allen County, KS for Ageratum?

Allen 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 Allen County's climate?

Yes — Ageratum grows well in Allen County's temperate climate. Allen County averages a 200-day frost-free season, with last frost around April 8 and first frost around October 25.

🌱

Your Allen County Garden Planner — Free

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

Sources & credits

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