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When to Plant Rosemary in Washington County, AL

Washington County, Alabama Zone 8b May

May in Washington County, Alabama — your action list

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Washington County, Alabama.

Avg. last frost March 12
Avg. first frost November 13
Soil temp (4") 74°F
Watering Low
Pest pressure High
Daylight 13.6 hrs
Looking ahead to June
  • First harvests: rosemary

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Rosemary is an aromatic evergreen shrub with needle-like leaves and a piney, citrus flavor. It is a Mediterranean herb that thrives in warm, dry conditions.

Washington County, Alabama is in USDA Zone 8b. The average last spring frost is March 12 and the first fall frost is November 13, giving you a growing season of approximately 246 days.

At an elevation of 419 feet, Washington County receives approximately 54.8 inches of rainfall annually with predominantly clay loam soil. Summer highs average 97°F, so Rosemary may need afternoon shade and extra watering during peak heat. Clay soil retains moisture well for Rosemary, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Rosemary root diseases.

Washington County, AL (Zone 8b) Long season
246 days
Last Spring Frost March 12
246 growing days
First Fall Frost November 13

Washington County Soil Profile

Soil Type

Clay Loam

Soil pH

5.3-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (16 days to spare)
Transplant: Mar 10 🍅 Harvest: Jun 2 – Oct 20
Recommended (50%) ✓ Fits season (15 days to spare)
Transplant: Mar 19 🍅 Harvest: Jun 11 – Oct 29
Safe Start (90%) ✓ Fits season (11 days to spare)
Transplant: Apr 11 🍅 Harvest: Jul 4 – Nov 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 Washington County

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

Soil pH

Your soil pH (5.3–6.6) is more acidic than Rosemary prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Rosemary.

How to Plant Rosemary

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Rosemary

3
successive plantings in your 246-day season

Sow every 9.1 weeks. Last sowing by May 17 to harvest before frost.

Plant Water Budget

Plant needs
0.3″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Rosemary

Rosemary needs approximately 0.3 inches of water per week (1.3" per month). Here's how your county's rainfall compares month by month.

Month Rosemary Needs Rainfall You Supplement Action
Jan 4.3" 0" ❄️ Dormant
Feb 5.1" 0" ❄️ Dormant
Mar 1.3" 5.4" 0" ✅ Rainfall sufficient
Apr 1.3" 3.7" 0" ✅ Rainfall sufficient
May 1.3" 4.8" 0" ✅ Rainfall sufficient
Jun 1.3" 4.5" 0" ✅ Rainfall sufficient
Jul 1.3" 5.1" 0" ✅ Rainfall sufficient
Aug 1.3" 5.4" 0" ✅ Rainfall sufficient
Sep 1.3" 3.6" 0" ✅ Rainfall sufficient
Oct 1.3" 3" 0" ✅ Rainfall sufficient
Nov 1.3" 4.8" 0" ✅ Rainfall sufficient
Dec 5" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Washington County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Rosemary 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.

Rosemary needs ~2,958 GDD — county provides 5,596 GDD Excellent fit

Rosemary Planting Timeline — Washington County, AL

Rosemary Planting Calendar

Activity When Date Range
Transplant Outdoors March 19 Mar 19 – Apr 2
Harvest June 11 Jun 11 – Oct 29

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Transplant Outdoors
April Transplant Outdoors
May
June Harvest
July Harvest
August Harvest
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.3"/week · Natural rainfall sufficient

📅 Days to Maturity

80–180 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8b

📆 Growing Season

246 days in Washington County

Growing Tips for Rosemary in Washington County

Direct sow Rosemary outdoors after March 12 in Washington County when soil has warmed and frost danger has passed.

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

With summer highs reaching 97°F in Washington County, provide afternoon shade for Rosemary and water deeply in the morning.

General growing tips

Grow in well-drained soil and avoid overwatering. In cold climates, grow in containers and bring indoors for winter. Propagate from stem cuttings for faster results than seed.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Rosemary in Washington County, AL?

Washington County is in Zone 8b with an average last frost of March 12. Plan your Rosemary planting based on this frost date — see the calendar above for exact timing.

What planting zone is Washington County, AL?

Washington County, Alabama is in USDA Hardiness Zone 8b. The average last spring frost is March 12 and first fall frost is November 13.

🌱

Your Washington County Garden Planner — Free

A 24-page printable planner built for Washington 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 Washington County, AL. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.