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When to Plant Rosemary in Gwinnett County, GA

Gwinnett County, Georgia Zone 8a May

Top priorities for Gwinnett County, Georgia gardeners in May

Each item below is timed to Gwinnett County, Georgia's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost March 22
Avg. first frost November 13
Soil temp (4") 68°F
Watering Low
Pest pressure Moderate
Daylight 13.8 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.

Gwinnett County, Georgia is in USDA Zone 8a. The average last spring frost is March 22 and the first fall frost is November 13, giving you a growing season of approximately 236 days.

At an elevation of 127 feet, Gwinnett County receives approximately 55.9 inches of rainfall annually with predominantly clay loam soil. Summer highs average 88°F, providing good warmth for Rosemary during the growing season. 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.

Gwinnett County, GA (Zone 8a) Long season
236 days
Last Spring Frost March 22
236 growing days
First Fall Frost November 13

Gwinnett County Soil Profile

Soil Type

Clay Loam

Soil pH

5.6-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (6 days to spare)
Transplant: Mar 18 🍅 Harvest: Jun 10 – Oct 28
Recommended (50%) ✓ Fits season (5 days to spare)
Transplant: Mar 29 🍅 Harvest: Jun 21 – Nov 8
Safe Start (90%) ✓ Fits season (4 days to spare)
Transplant: Apr 16 🍅 Harvest: Jul 9 – Nov 26

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 Gwinnett County

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

Soil pH

Your soil pH (5.6–6.6) overlaps with Rosemary's range (6.0–7.5), though not a perfect match.

Soil Texture

The clay loam soil in Gwinnett 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 236-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
1.0″/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 4.7" 0" ❄️ Dormant
Feb 4.6" 0" ❄️ Dormant
Mar 1.3" 5.7" 0" ✅ Rainfall sufficient
Apr 1.3" 4.2" 0" ✅ Rainfall sufficient
May 1.3" 4.2" 0" ✅ Rainfall sufficient
Jun 1.3" 4.7" 0" ✅ Rainfall sufficient
Jul 1.3" 6" 0" ✅ Rainfall sufficient
Aug 1.3" 5.8" 0" ✅ Rainfall sufficient
Sep 1.3" 3.7" 0" ✅ Rainfall sufficient
Oct 1.3" 3.8" 0" ✅ Rainfall sufficient
Nov 1.3" 4.5" 0" ✅ Rainfall sufficient
Dec 3.9" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Gwinnett 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 ~2,080 GDD — county provides 3,776 GDD Excellent fit

Rosemary Planting Timeline — Gwinnett County, GA

Rosemary Planting Calendar

Activity When Date Range
Transplant Outdoors March 29 Mar 29 – Apr 12
Harvest June 21 Jun 21 – Nov 8

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 Harvest
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: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

236 days in Gwinnett County

Growing Tips for Rosemary in Gwinnett County

Direct sow Rosemary outdoors after March 22 in Gwinnett County when soil has warmed and frost danger has passed.

With Gwinnett County's clay soil (32% clay), work in 3-4 inches of compost before planting Rosemary. Avoid tilling when soil is wet to prevent compaction.

With 56" of annual rainfall in Gwinnett County, ensure good drainage for Rosemary — excess moisture can promote root rot and fungal diseases.

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 Gwinnett County, GA?

Gwinnett County is in Zone 8a with an average last frost of March 22. Plan your Rosemary planting based on this frost date — see the calendar above for exact timing.

What planting zone is Gwinnett County, GA?

Gwinnett County, Georgia is in USDA Hardiness Zone 8a. The average last spring frost is March 22 and first fall frost is November 13.

🌱

Your Gwinnett County Garden Planner — Free

A 24-page printable planner built for Gwinnett 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 Gwinnett County, GA. 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.