Blog

When to plant Ageratum in Marshall County, AL

Plant Ageratum in Marshall County from March 29 to April 19 in spring. Marshall County sits in USDA Zone 8a, with last frost around April 5 and first frost on October 31.

When to Plant Ageratum in Marshall County, AL

Marshall County, Alabama Zone 8a June

June in the garden — Marshall County, Alabama

June is a pivotal month for Marshall County, Alabama gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 5
Avg. first frost October 31
Soil temp (4") 78°F
Watering Low
Pest pressure High
Daylight 14.3 hrs
  1. Basket week: ageratum

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

Coming up in July — start thinking about
  • 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.

Marshall County, Alabama is in USDA Zone 8a. The average last spring frost is April 5 and the first fall frost is October 31, giving you a growing season of approximately 209 days.

At an elevation of 159 feet, Marshall County receives approximately 60.2 inches of rainfall annually with predominantly clay loam soil. Summer highs average 89°F, providing good warmth for Ageratum during the growing season. Clay soil retains moisture well for Ageratum, but amend with compost to improve drainage and prevent root rot. 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
Marshall County, AL (Zone 8a) Long season
209 days
Last Spring Frost April 5
209 growing days
First Fall Frost October 31

Marshall County Soil Profile

Soil Type

Clay Loam

Soil pH

5.5-6.6

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (21 days to spare)
Start indoors: Feb 13 Transplant: Mar 20 🌸 Bloom: May 15 – Oct 2
Recommended (50%) ✓ Fits season (20 days to spare)
Start indoors: Feb 22 Transplant: Mar 29 🌸 Bloom: May 24 – Oct 11
Safe Start (90%) ✓ Fits season (20 days to spare)
Start indoors: Mar 7 Transplant: Apr 11 🌸 Bloom: Jun 6 – Oct 24

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 Marshall County

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

Soil pH

Your soil pH (5.5–6.6) overlaps with Ageratum's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

4
successive plantings in your 209-day season

Sow every 6.9 weeks. Last sowing by Aug 17 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

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 5" 0" ❄️ Dormant
Feb 5.3" 0" ❄️ Dormant
Mar 5.4" 0" ❄️ Dormant
Apr 4.3" 4.7" 0" ✅ Rainfall sufficient
May 4.3" 4.8" 0" ✅ Rainfall sufficient
Jun 4.3" 5" 0" ✅ Rainfall sufficient
Jul 4.3" 6.7" 0" ✅ Rainfall sufficient
Aug 4.3" 5.4" 0" ✅ Rainfall sufficient
Sep 4.3" 4.2" 0.1" 💧 Light watering
Oct 4.3" 4.2" 0.1" 💧 Light watering
Nov 5.1" 0" ❄️ Dormant
Dec 4.4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Marshall 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 3,500 GDD Excellent fit

Ageratum Planting Timeline — Marshall County, AL

Ageratum Planting Calendar

Activity When Date Range
Start Indoors February 22 Feb 22 – Mar 8
Transplant Outdoors March 29 Mar 29 – Apr 12
Direct Sow March 29 Mar 29 – Apr 19
Bloom May 24 May 24 – Oct 11

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors Transplant Outdoors Direct Sow
April Transplant Outdoors Direct Sow
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 · Natural rainfall sufficient

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

209 days in Marshall County

Growing Tips for Ageratum in Marshall County

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

With Marshall County's clay soil (34% clay), work in 3-4 inches of compost before planting Ageratum. Avoid tilling when soil is wet to prevent compaction.

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 Marshall County, AL?

Marshall County is in Zone 8a with an average last frost of April 5. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Marshall County, AL?

Marshall County, Alabama is in USDA Hardiness Zone 8a. The average last spring frost is April 5 and first fall frost is October 31.

When should I plant Ageratum in Marshall County, AL?

In Marshall County, AL, plant Ageratum after the last frost (around April 5) and before the first frost (around October 31). Best results when soil holds above 50°F.

What growing zone is Marshall County, AL for Ageratum?

Marshall County sits in USDA Zone 8a. Ageratum grows reliably in zones 3a through 11b, so it's a good fit here.

Can Ageratum grow in Marshall County's climate?

Yes — Ageratum grows well in Marshall County's temperate climate. Marshall County averages a 209-day frost-free season, with last frost around April 5 and first frost around October 31.

🌱

Your Marshall County Garden Planner — Free

A 22-page printable planner built for Marshall County (Zone 8a). 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 Marshall County, AL. 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.