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When to plant Ageratum in Smith County, MS

In Zone 8b (Smith County), direct-sow Ageratum between February 27 and March 20 for spring, after the March 13 last-frost mark.

When to Plant Ageratum in Smith County, MS

Smith County, Mississippi Zone 8b June

June to-do list for Smith County, Mississippi

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

Avg. last frost March 13
Avg. first frost November 13
Soil temp (4") 83°F
Watering Low
Pest pressure High
Daylight 14.1 hrs
  1. It's harvest week for ageratum

    If you can't use it all right away, check the food-preservation section of your planner.

To set up a strong July, finish these tasks
  • 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.

Smith County, Mississippi is in USDA Zone 8b. The average last spring frost is March 13 and the first fall frost is November 13, giving you a growing season of approximately 245 days.

At an elevation of 492 feet, Smith County receives approximately 58.4 inches of rainfall annually with predominantly clay loam soil. Summer highs average 96°F, so Ageratum may need afternoon shade and extra watering during peak heat. 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
Smith County, MS (Zone 8b) Long season
245 days
Last Spring Frost March 13
245 growing days
First Fall Frost November 13

Smith County Soil Profile

Soil Type

Clay Loam

Soil pH

5.7-6.5

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (48 days to spare)
Start indoors: Jan 23 Transplant: Feb 20 🌸 Bloom: Apr 17 – Sep 18
Recommended (50%) ✓ Fits season (49 days to spare)
Start indoors: Jan 30 Transplant: Feb 27 🌸 Bloom: Apr 24 – Sep 25
Safe Start (90%) ✓ Fits season (40 days to spare)
Start indoors: Feb 24 Transplant: Mar 24 🌸 Bloom: May 19 – Oct 20

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

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

4
successive plantings in your 245-day season

Sow every 6.9 weeks. Last sowing by Aug 30 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/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 5.2" 0" ❄️ Dormant
Feb 5.1" 0" ❄️ Dormant
Mar 4.3" 5.6" 0" ✅ Rainfall sufficient
Apr 4.3" 3.8" 0.5" 💧 Light watering
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 5.2" 0" ✅ Rainfall sufficient
Jul 4.3" 6" 0" ✅ Rainfall sufficient
Aug 4.3" 5.1" 0" ✅ Rainfall sufficient
Sep 4.3" 4.8" 0" ✅ Rainfall sufficient
Oct 4.3" 4.1" 0.2" 💧 Light watering
Nov 4.3" 4.2" 0.1" 💧 Light watering
Dec 4.7" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Smith 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 5,390 GDD Excellent fit

Ageratum Planting Timeline — Smith County, MS

Ageratum Planting Calendar

Activity When Date Range
Start Indoors January 30 Jan 30 – Feb 13
Transplant Outdoors February 27 Feb 27 – Mar 13
Direct Sow February 27 Feb 27 – Mar 20
Bloom April 24 Apr 24 – Sep 25

· 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
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 8b

📆 Growing Season

245 days in Smith County

Growing Tips for Ageratum in Smith County

Direct sow Ageratum outdoors after March 13 in Smith County when soil has warmed and frost danger has passed.

With Smith County's clay soil (33% clay), work in 3-4 inches of compost before planting Ageratum. Avoid tilling when soil is wet to prevent compaction.

With summer highs reaching 96°F in Smith 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 Smith County, MS?

Smith County is in Zone 8b with an average last frost of March 13. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Smith County, MS?

Smith County, Mississippi is in USDA Hardiness Zone 8b. The average last spring frost is March 13 and first fall frost is November 13.

When should I plant Ageratum in Smith County, MS?

In Smith County, MS, plant Ageratum after the last frost (around March 13) and before the first frost (around November 13). Best results when soil holds above 50°F.

What growing zone is Smith County, MS for Ageratum?

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

Can Ageratum grow in Smith County's climate?

Yes — Ageratum grows well in Smith County's temperate climate. Smith County averages a 245-day frost-free season, with last frost around March 13 and first frost around November 13.

🌱

Your Smith County Garden Planner — Free

A 22-page printable planner built for Smith County (Zone 8b). 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 Smith County, MS. Local conditions may vary. Last updated: June 2026.

Sources & credits

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