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When to Plant Ageratum in Bryan County, OK

Bryan County, Oklahoma Zone 8a June

June to-do list for Bryan County, Oklahoma

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Bryan County, Oklahoma.

Avg. last frost March 25
Avg. first frost November 11
Soil temp (4") 78°F
Watering Moderate
Pest pressure High
Daylight 14.3 hrs
  1. Harvest ageratum as they ripen

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

July 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.

Bryan County, Oklahoma is in USDA Zone 8a. The average last spring frost is March 25 and the first fall frost is November 11, giving you a growing season of approximately 231 days.

At an elevation of 928 feet, Bryan County receives approximately 22.3 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Ageratum during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
Bryan County, OK (Zone 8a) Long season
231 days
Last Spring Frost March 25
231 growing days
First Fall Frost November 11

Bryan County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.1

Drainage

Well Drained

Ageratum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (47 days to spare)
Start indoors: Jan 28 Transplant: Mar 4 🌸 Bloom: Apr 29 – Sep 16
Recommended (50%) ✓ Fits season (42 days to spare)
Start indoors: Feb 11 Transplant: Mar 18 🌸 Bloom: May 13 – Sep 30
Safe Start (90%) ✓ Fits season (40 days to spare)
Start indoors: Mar 4 Transplant: Apr 8 🌸 Bloom: Jun 3 – Oct 21

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 Bryan County

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

Soil pH

Your soil pH (6.2–7.1) overlaps with Ageratum's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.7%). Annual compost additions will help Ageratum.

How to Plant Ageratum

8"
Between Plants
10"
Between Rows

Succession Planting Ageratum

4
successive plantings in your 231-day season

Sow every 6.9 weeks. Last sowing by Aug 28 to harvest before frost.

Ageratum Water Budget

Plant needs
1.0″/week
Rainfall provides
0.4″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 1,467 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 0.5" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 4.3" 1.6" 2.7" 🚿 Regular watering
Apr 4.3" 2.3" 2" 💧 Light watering
May 4.3" 3" 1.3" 💧 Light watering
Jun 4.3" 3.6" 0.7" 💧 Light watering
Jul 4.3" 2.8" 1.5" 💧 Light watering
Aug 4.3" 2.6" 1.7" 💧 Light watering
Sep 4.3" 2.4" 1.9" 💧 Light watering
Oct 4.3" 1.5" 2.8" 🚿 Regular watering
Nov 4.3" 0.8" 3.5" 🚿 Regular watering
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Bryan 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 ~1,181 GDD — county provides 4,042 GDD Excellent fit

Ageratum Planting Timeline — Bryan County, OK

Ageratum Planting Calendar

Activity When Date Range
Start Indoors February 11 Feb 11 – Feb 25
Transplant Outdoors March 18 Mar 18 – Apr 1
Direct Sow March 18 Mar 18 – Apr 8
Bloom May 13 May 13 – Sep 30

· 8" apart · Rows 10" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

60–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

231 days in Bryan County

Growing Tips for Ageratum in Bryan County

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

Common pests for Ageratum in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

Bryan County receives only 22" of rain annually. Ageratum needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Bryan County, OK?

Bryan County is in Zone 8a with an average last frost of March 25. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Bryan County, OK?

Bryan County, Oklahoma is in USDA Hardiness Zone 8a. The average last spring frost is March 25 and first fall frost is November 11.

🌱

Your Bryan County Garden Planner — Free

A 22-page printable planner built for Bryan 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.

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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 Bryan County, OK. 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.