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When to plant Ageratum in Boone County, KY

Boone County's spring Ageratum window runs April 19 through May 10. time plantings around the expected last-frost window for best survival.

When to Plant Ageratum in Boone County, KY

Boone County, Kentucky Zone 6b June

Top priorities for Boone County, Kentucky gardeners in June

Each item below is timed to Boone County, Kentucky's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 19
Avg. first frost October 21
Soil temp (4") 69°F
Watering Low
Pest pressure High
Daylight 14.7 hrs
  1. Fire up the seed-starting tray: ageratum

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

  2. Bring in the ageratum

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

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.

Boone County, Kentucky is in USDA Zone 6b. The average last spring frost is April 19 and the first fall frost is October 21, giving you a growing season of approximately 185 days.

At an elevation of 2,587 feet, Boone County receives approximately 51 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Ageratum during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Ageratum root diseases.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Boone County, KY (Zone 6b) Moderate season
185 days
Last Spring Frost April 19
185 growing days
First Fall Frost October 21

Boone County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.5

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (28 days to spare)
Start indoors: Feb 21 Transplant: Apr 11 🌸 Bloom: Jun 6 – Sep 19
Recommended (50%) ✓ Fits season (24 days to spare)
Start indoors: Mar 1 Transplant: Apr 19 🌸 Bloom: Jun 14 – Sep 27
Safe Start (90%) ✓ Fits season (16 days to spare)
Start indoors: Mar 21 Transplant: May 9 🌸 Bloom: Jul 4 – Oct 17

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 Boone County

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

Soil pH

Your soil pH (5.7–6.5) overlaps with Ageratum's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

3
successive plantings in your 185-day season

Sow every 6.9 weeks. Last sowing by Aug 07 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 4.7" 0" ❄️ Dormant
Feb 4.1" 0" ❄️ Dormant
Mar 5.2" 0" ❄️ Dormant
Apr 4.3" 3.7" 0.6" 💧 Light watering
May 4.3" 3.6" 0.7" 💧 Light watering
Jun 4.3" 5.1" 0" ✅ Rainfall sufficient
Jul 4.3" 5.2" 0" ✅ Rainfall sufficient
Aug 4.3" 4.4" 0" ✅ Rainfall sufficient
Sep 4.3" 4.3" 0" ✅ Rainfall sufficient
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 3.9" 0" ❄️ Dormant
Dec 3.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Boone 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 ~1,131 GDD — county provides 3,098 GDD Excellent fit

Ageratum Planting Timeline — Boone County, KY

Ageratum Planting Calendar

Activity When Date Range
Start Indoors March 1 Mar 1 – Mar 15
Transplant Outdoors April 19 Apr 19 – May 3
Direct Sow April 19 Apr 19 – May 10
Bloom June 14 Jun 14 – Sep 27

· 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 · Natural rainfall sufficient

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

185 days in Boone County

Growing Tips for Ageratum in Boone County

Direct sow Ageratum outdoors after April 19 in Boone 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 Boone County, KY?

Boone County is in Zone 6b with an average last frost of April 19. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Boone County, KY?

Boone County, Kentucky is in USDA Hardiness Zone 6b. The average last spring frost is April 19 and first fall frost is October 21.

When should I plant Ageratum in Boone County, KY?

In Boone County, KY, plant Ageratum after the last frost (around April 19) and before the first frost (around October 21). Best results when soil holds above 50°F.

What growing zone is Boone County, KY for Ageratum?

Boone 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 Boone County's climate?

Yes — Ageratum grows well in Boone County's temperate climate. Boone County averages a 185-day frost-free season, with last frost around April 19 and first frost around October 21.

🌱

Your Boone County Garden Planner — Free

A 22-page printable planner built for Boone 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 Boone County, KY. 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.