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When to Plant Ageratum in Cass County, NE

Cass County, Nebraska Zone 6a June

Cass County, Nebraska gardeners: here's your June plan

Your garden in Cass County, Nebraska is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost April 22
Avg. first frost October 11
Soil temp (4") 68°F
Watering Moderate
Pest pressure High
Daylight 14.9 hrs
  1. Get ageratum seeds going inside

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

  2. It's harvest week for ageratum

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

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.

Cass County, Nebraska is in USDA Zone 6a. The average last spring frost is April 22 and the first fall frost is October 11, giving you a growing season of approximately 172 days.

At an elevation of 779 feet, Cass County receives approximately 20.7 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Ageratum during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Cass County, NE (Zone 6a) Moderate season
172 days
Last Spring Frost April 22
172 growing days
First Fall Frost October 11

Cass County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.8

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (19 days to spare)
Start indoors: Feb 26 Transplant: Apr 16 🌸 Bloom: Jun 11 – Sep 17
Recommended (50%) ✓ Fits season (18 days to spare)
Start indoors: Mar 4 Transplant: Apr 22 🌸 Bloom: Jun 17 – Sep 23
Safe Start (90%) ✓ Fits season (22 days to spare)
Start indoors: Mar 15 Transplant: May 3 🌸 Bloom: Jun 28 – Oct 4

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 Cass County

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

Soil pH

Your soil pH (6.3–7.8) is more alkaline than Ageratum prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.6%). Annual compost additions will help Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

3
successive plantings in your 172-day season

Sow every 6.9 weeks. Last sowing by Jul 28 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 908 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 0.5" 0" ❄️ Dormant
Feb 0.6" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 4.3" 2.2" 2.1" 💧 Light watering
May 4.3" 2.6" 1.7" 💧 Light watering
Jun 4.3" 3" 1.3" 💧 Light watering
Jul 4.3" 2.8" 1.5" 💧 Light watering
Aug 4.3" 2.7" 1.6" 💧 Light watering
Sep 4.3" 2.2" 2.1" 💧 Light watering
Oct 4.3" 1.3" 3" 🚿 Regular watering
Nov 0.6" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Cass 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 ~979 GDD — county provides 2,494 GDD Excellent fit

Ageratum Planting Timeline — Cass County, NE

Ageratum Planting Calendar

Activity When Date Range
Start Indoors March 4 Mar 4 – Mar 18
Transplant Outdoors April 22 Apr 22 – May 6
Direct Sow April 22 Apr 22 – May 13
Bloom June 17 Jun 17 – Sep 23

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January
February
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

1"/week · 1-2 times/week

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

172 days in Cass County

Growing Tips for Ageratum in Cass County

Direct sow Ageratum outdoors after April 22 in Cass 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.

Cass County receives only 21" of rain annually. Ageratum needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Cass County, NE?

Cass County is in Zone 6a with an average last frost of April 22. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cass County, NE?

Cass County, Nebraska is in USDA Hardiness Zone 6a. The average last spring frost is April 22 and first fall frost is October 11.

🌱

Your Cass County Garden Planner — Free

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

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.