Blog

When to plant Ageratum in Dundee, FL

For Ageratum in Dundee, the safe spring window opens around December 21 and closes around January 11. Last expected frost is January 25, first fall frost December 19, giving a 329-day growing season.

When to Plant Ageratum in Dundee, FL

Polk County, Florida Zone 10a June

June to-do list for Polk County, Florida

Welcome to June in Zone 10a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost January 25
Avg. first frost December 19
Soil temp (4") 89°F
Watering Low
Pest pressure High
Daylight 13.8 hrs
  1. Start harvesting ageratum

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

July will be here before you know it — start on
  • First harvests: ageratum

Instant PDF download. No spam, unsubscribe any time.

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.

Dundee, Florida is in USDA Zone 10a. The average last spring frost is January 25 and the first fall frost is December 19, giving you a growing season of approximately 328 days.

At an elevation of 236 feet, Polk County receives approximately 58.3 inches of rainfall annually with predominantly sand soil. Summer highs average 96°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
Dundee, FL (Zone 10a) Year-round
328 days
Last Spring Frost January 25
328 growing days
First Fall Frost December 19

Dundee Soil Profile

Soil Type

Sand

Soil pH

4.9-6.3

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (108 days to spare)
Start indoors: Dec 8 Transplant: Dec 15 🌸 Bloom: Feb 9 – Aug 24
Recommended (50%) ✓ Fits season (111 days to spare)
Start indoors: Dec 14 Transplant: Dec 21 🌸 Bloom: Feb 15 – Aug 30
Safe Start (90%) ✓ Fits season (90 days to spare)
Start indoors: Jan 9 Transplant: Jan 16 🌸 Bloom: Mar 13 – Sep 25

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 Dundee

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

Soil pH

Your soil pH (4.9–6.3) is more acidic than Ageratum prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in Polk 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 328-day season

Sow every 6.9 weeks. Last sowing by Oct 05 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 1,627 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 4.3" 2.5" 1.8" 💧 Light watering
Feb 4.3" 3.1" 1.2" 💧 Light watering
Mar 4.3" 3.5" 0.8" 💧 Light watering
Apr 4.3" 2.6" 1.7" 💧 Light watering
May 4.3" 4.2" 0.1" 💧 Light watering
Jun 4.3" 9" 0" ✅ Rainfall sufficient
Jul 4.3" 9.1" 0" ✅ Rainfall sufficient
Aug 4.3" 7.9" 0" ✅ Rainfall sufficient
Sep 4.3" 6.7" 0" ✅ Rainfall sufficient
Oct 4.3" 4.8" 0" ✅ Rainfall sufficient
Nov 4.3" 2.4" 1.9" 💧 Light watering
Dec 4.3" 2.4" 1.9" 💧 Light watering

Water needs are for active growing months only (Jan–Dec in Polk 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 ~1,485 GDD — county provides 7,238 GDD Excellent fit

Ageratum Planting Timeline — Dundee, FL

Ageratum Planting Calendar

Activity When Date Range
Start Indoors December 14 Dec 14 – Dec 28
Transplant Outdoors December 21 Dec 21 – Jan 4
Direct Sow December 21 Dec 21 – Jan 11
Bloom February 15 Feb 15 – Aug 30

· 8" apart · Rows 10" apart

Month-by-Month Timeline

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

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 10a

📆 Growing Season

328 days in Polk County

Growing Tips for Ageratum in Dundee

Direct sow Ageratum outdoors after January 25 in Polk County when soil has warmed and frost danger has passed.

Sandy soil in Polk 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 96°F in Polk 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 →

When should I plant Ageratum in Dundee, FL?

In Dundee, FL, plant Ageratum after the last frost (around January 25) and before the first frost (around December 19). Best results when soil holds above 50°F.

What growing zone is Dundee, FL for Ageratum?

Dundee sits in USDA Zone 10a. Ageratum grows reliably in zones 3a through 11b, so it's a good fit here.

Can Ageratum grow in Dundee's climate?

Yes — Ageratum grows well in Dundee's temperate climate. Dundee averages a 329-day frost-free season, with last frost around January 25 and first frost around December 19.

🌱

Your Polk County Garden Planner — Free

A 22-page printable planner built for Polk County (Zone 10a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Polk County, FL. Local conditions may vary. Last updated: June 2026.