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When to plant Ageratum in Jefferson County, FL

In Zone 9a (Jefferson County), direct-sow Ageratum between February 23 and March 16 for spring, after the March 9 last-frost mark.

When to Plant Ageratum in Jefferson County, FL

Jefferson County, Florida Zone 9a July

Your July planting checklist for Jefferson County, Florida

We've pulled the most time-sensitive tasks for Jefferson County, Florida this July and put them front and centre. Tackle them in order.

Avg. last frost March 9
Avg. first frost November 21
Soil temp (4") 91°F
Watering Low
Pest pressure High
Daylight 13.8 hrs
  1. It's harvest week for ageratum

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

August prep starts now
  • 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.

Jefferson County, Florida is in USDA Zone 9a. The average last spring frost is March 9 and the first fall frost is November 21, giving you a growing season of approximately 257 days.

At an elevation of 105 feet, Jefferson County receives approximately 56 inches of rainfall annually with predominantly sand soil. Summer highs average 95°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
Jefferson County, FL (Zone 9a) Long season
257 days
Last Spring Frost March 9
257 growing days
First Fall Frost November 21

Jefferson County Soil Profile

Soil Type

Sand

Soil pH

5.2-5.9

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (42 days to spare)
Start indoors: Jan 21 Transplant: Feb 18 🌸 Bloom: Apr 15 – Sep 30
Recommended (50%) ✓ Fits season (47 days to spare)
Start indoors: Jan 26 Transplant: Feb 23 🌸 Bloom: Apr 20 – Oct 5
Safe Start (90%) ✓ Fits season (50 days to spare)
Start indoors: Feb 13 Transplant: Mar 13 🌸 Bloom: May 8 – Oct 23

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 Jefferson County

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

Soil pH

Your soil pH (5.2–5.9) is more acidic than Ageratum prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in Jefferson 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 (1.3%). Add 2-3 inches of compost before planting Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

5
successive plantings in your 257-day season

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

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 880 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 3" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 4.3" 3.2" 1.1" 💧 Light watering
Apr 4.3" 2.4" 1.9" 💧 Light watering
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 7.8" 0" ✅ Rainfall sufficient
Jul 4.3" 8.9" 0" ✅ Rainfall sufficient
Aug 4.3" 7.4" 0" ✅ Rainfall sufficient
Sep 4.3" 6.4" 0" ✅ Rainfall sufficient
Oct 4.3" 5" 0" ✅ Rainfall sufficient
Nov 4.3" 2.5" 1.8" 💧 Light watering
Dec 2.7" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Jefferson 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 ~1,434 GDD — county provides 5,461 GDD Excellent fit

Ageratum Planting Timeline — Jefferson County, FL

Ageratum Planting Calendar

Activity When Date Range
Start Indoors January 26 Jan 26 – Feb 9
Transplant Outdoors February 23 Feb 23 – Mar 9
Direct Sow February 23 Feb 23 – Mar 16
Bloom April 20 Apr 20 – Oct 5

· 8" apart · Rows 10" apart

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 9a

📆 Growing Season

257 days in Jefferson County

Growing Tips for Ageratum in Jefferson County

Direct sow Ageratum outdoors after March 09 in Jefferson County when soil has warmed and frost danger has passed.

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

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 Jefferson County, FL?

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

What planting zone is Jefferson County, FL?

Jefferson County, Florida is in USDA Hardiness Zone 9a. The average last spring frost is March 9 and first fall frost is November 21.

When should I plant Ageratum in Jefferson County, FL?

In Jefferson County, FL, plant Ageratum after the last frost (around March 9) and before the first frost (around November 21). Best results when soil holds above 50°F.

What growing zone is Jefferson County, FL for Ageratum?

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

Can Ageratum grow in Jefferson County's climate?

Yes — Ageratum grows well in Jefferson County's temperate climate. Jefferson County averages a 257-day frost-free season, with last frost around March 9 and first frost around November 21.

🌱

Your Jefferson County Garden Planner — Free

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

Sources & credits

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