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When to plant Ageratum in Flagler County, FL

Plant Ageratum in Flagler County after February 5; the prime window is January 15–February 5.

When to Plant Ageratum in Flagler County, FL

Flagler County, Florida Zone 9b July

July to-do list for Flagler County, Florida

Welcome to July in Zone 9b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost February 5
Avg. first frost December 17
Soil temp (4") 94°F
Watering Low
Pest pressure High
Daylight 13.7 hrs
  1. Start harvesting ageratum

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Before August arrives, get these ready
  • 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.

Flagler County, Florida is in USDA Zone 9b. The average last spring frost is February 5 and the first fall frost is December 17, giving you a growing season of approximately 315 days.

At an elevation of 134 feet, Flagler County receives approximately 54.2 inches of rainfall annually with predominantly sand soil. Summer highs average 99°F, so Ageratum may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Ageratum will need more frequent watering and organic matter to retain nutrients. 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
Flagler County, FL (Zone 9b) Year-round
315 days
Last Spring Frost February 5
315 growing days
First Fall Frost December 17

Flagler County Soil Profile

Soil Type

Sand

Soil pH

5.1-5.7

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (103 days to spare)
Start indoors: Dec 11 Transplant: Jan 1 🌸 Bloom: Feb 26 – Aug 27
Recommended (50%) ✓ Fits season (98 days to spare)
Start indoors: Dec 25 Transplant: Jan 15 🌸 Bloom: Mar 12 – Sep 10
Safe Start (90%) ✓ Fits season (84 days to spare)
Start indoors: Jan 17 Transplant: Feb 7 🌸 Bloom: Apr 4 – Oct 3

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 Flagler County

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

Soil pH

Your soil pH (5.1–5.7) is more acidic than Ageratum prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in Flagler County warms quickly in spring but drains fast. Ageratum will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Ageratum.

Organic Matter

Organic matter is low (1.6%). Add 2-3 inches of compost before planting Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

6
successive plantings in your 315-day season

Sow every 6.9 weeks. Last sowing by Oct 03 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,630 gal / 100 sq ft

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 2.7" 0" ❄️ Dormant
Feb 4.3" 2.5" 1.8" 💧 Light watering
Mar 4.3" 3" 1.3" 💧 Light watering
Apr 4.3" 2.2" 2.1" 💧 Light watering
May 4.3" 3.7" 0.6" 💧 Light watering
Jun 4.3" 8.8" 0" ✅ Rainfall sufficient
Jul 4.3" 7.7" 0" ✅ Rainfall sufficient
Aug 4.3" 7.4" 0" ✅ Rainfall sufficient
Sep 4.3" 6.9" 0" ✅ Rainfall sufficient
Oct 4.3" 4.7" 0" ✅ Rainfall sufficient
Nov 4.3" 2" 2.3" 🚿 Regular watering
Dec 4.3" 2.5" 1.8" 💧 Light watering

Water needs are for active growing months only (Feb–Dec in Flagler 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 ~1,637 GDD — county provides 7,663 GDD Excellent fit

Ageratum Planting Timeline — Flagler County, FL

Ageratum Planting Calendar

Activity When Date Range
Start Indoors December 25 Dec 25 – Jan 8
Transplant Outdoors January 15 Jan 15 – Jan 29
Direct Sow January 15 Jan 15 – Feb 5
Bloom March 12 Mar 12 – Sep 10

· 8" apart · Rows 10" apart

Month-by-Month Timeline

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

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_acidic

🗺️ USDA Zone

Zone 9b

📆 Growing Season

315 days in Flagler County

Growing Tips for Ageratum in Flagler County

Direct sow Ageratum outdoors after February 05 in Flagler County when soil has warmed and frost danger has passed.

Sandy soil in Flagler County dries quickly — mulch Ageratum with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 99°F in Flagler County, provide afternoon shade for Ageratum and water deeply in the morning.

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 Flagler County, FL?

Flagler County is in Zone 9b with an average last frost of February 5. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Flagler County, FL?

Flagler County, Florida is in USDA Hardiness Zone 9b. The average last spring frost is February 5 and first fall frost is December 17.

When should I plant Ageratum in Flagler County, FL?

In Flagler County, FL, plant Ageratum after the last frost (around February 5) and before the first frost (around December 17). Best results when soil holds above 50°F.

What growing zone is Flagler County, FL for Ageratum?

Flagler County sits in USDA Zone 9b. Ageratum grows reliably in zones 3a through 11b, so it's a good fit here.

Can Ageratum grow in Flagler County's climate?

Yes — Ageratum grows well in Flagler County's temperate climate. Flagler County averages a 316-day frost-free season, with last frost around February 5 and first frost around December 17.

🌱

Your Flagler County Garden Planner — Free

A 22-page printable planner built for Flagler County (Zone 9b). 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 Flagler County, FL. Local conditions may vary. Last updated: July 2026.

Sources & credits

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