Blog

When to Plant Rosemary in Mobile County, AL

Mobile County, Alabama Zone 9a May

May in the garden — Mobile County, Alabama

Your garden in Mobile County, Alabama is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost March 3
Avg. first frost November 24
Soil temp (4") 71°F
Watering Moderate
Pest pressure High
Daylight 13.6 hrs
June will be here before you know it — start on
  • First harvests: rosemary

Instant PDF download. No spam, unsubscribe any time.

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.

Mobile County, Alabama is in USDA Zone 9a. The average last spring frost is March 3 and the first fall frost is November 24, giving you a growing season of approximately 266 days.

At an elevation of 101 feet, Mobile County receives approximately 48.3 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 97°F, so Rosemary may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Rosemary will need more frequent watering and organic matter to retain nutrients.

Mobile County, AL (Zone 9a) Long season
266 days
Last Spring Frost March 3
266 growing days
First Fall Frost November 24

Mobile County Soil Profile

Soil Type

Sandy Loam

Soil pH

4.8-6.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (40 days to spare)
Transplant: Feb 26 🍅 Harvest: May 21 – Oct 8
Recommended (50%) ✓ Fits season (35 days to spare)
Transplant: Mar 10 🍅 Harvest: Jun 2 – Oct 20
Safe Start (90%) ✓ Fits season (35 days to spare)
Transplant: Mar 27 🍅 Harvest: Jun 19 – Nov 6

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 Mobile County

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

Soil pH

Your soil pH (4.8–6.1) is more acidic than Rosemary prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

Sandy soil in Mobile County warms quickly in spring but drains fast. Rosemary will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Rosemary prefers dry conditions but your soil drains poorly. Use raised beds or mounded rows to prevent root rot.

Organic Matter

Organic matter is moderate (2.2%). 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 266-day season

Sow every 9.1 weeks. Last sowing by May 28 to harvest before frost.

Plant Water Budget

Plant needs
0.3″/week
Rainfall provides
0.8″/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 3.7" 0" ❄️ Dormant
Feb 3.5" 0" ❄️ Dormant
Mar 1.3" 4.9" 0" ✅ Rainfall sufficient
Apr 1.3" 3.7" 0" ✅ Rainfall sufficient
May 1.3" 3.5" 0" ✅ Rainfall sufficient
Jun 1.3" 4" 0" ✅ Rainfall sufficient
Jul 1.3" 5.5" 0" ✅ Rainfall sufficient
Aug 1.3" 4.2" 0" ✅ Rainfall sufficient
Sep 1.3" 3.6" 0" ✅ Rainfall sufficient
Oct 1.3" 3.5" 0" ✅ Rainfall sufficient
Nov 1.3" 4.3" 0" ✅ Rainfall sufficient
Dec 4" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Mobile 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 6,051 GDD Excellent fit

Rosemary Planting Timeline — Mobile County, AL

Rosemary Planting Calendar

Activity When Date Range
Transplant Outdoors March 10 Mar 10 – Mar 24
Harvest June 2 Jun 2 – Oct 20

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

Month-by-Month Timeline

MonthActivities
January
February
March Transplant Outdoors
April
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 9a

📆 Growing Season

266 days in Mobile County

Growing Tips for Rosemary in Mobile County

Direct sow Rosemary outdoors after March 03 in Mobile County when soil has warmed and frost danger has passed.

Sandy soil in Mobile County dries quickly — mulch Rosemary with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 97°F in Mobile 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 Mobile County, AL?

Mobile County is in Zone 9a with an average last frost of March 3. Plan your Rosemary planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mobile County, AL?

Mobile County, Alabama is in USDA Hardiness Zone 9a. The average last spring frost is March 3 and first fall frost is November 24.

🌱

Your Mobile County Garden Planner — Free

A 24-page printable planner built for Mobile County (Zone 9a). 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 Mobile 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.