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When to Plant Rosemary in Lamar County, TX

Lamar County, Texas Zone 8a May

Lamar County, Texas gardeners: here's your May plan

A quick May briefing for Lamar County, Texas gardeners — what's urgent, what's next, and what can wait.

Avg. last frost March 15
Avg. first frost November 15
Soil temp (4") 69°F
Watering Low
Pest pressure Moderate
Daylight 13.7 hrs
A few tasks this May that'll pay off in 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.

Lamar County, Texas is in USDA Zone 8a. The average last spring frost is March 15 and the first fall frost is November 15, giving you a growing season of approximately 245 days.

At an elevation of 95 feet, Lamar County receives approximately 59.8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 91°F, providing good warmth for Rosemary during the growing season. Sandy soil warms quickly in spring — great for early planting — but Rosemary will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Rosemary root diseases.

Lamar County, TX (Zone 8a) Long season
245 days
Last Spring Frost March 15
245 growing days
First Fall Frost November 15
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Lamar County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.8-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (10 days to spare)
Transplant: Mar 14 🍅 Harvest: Jun 6 – Oct 24
Recommended (50%) ✓ Fits season (14 days to spare)
Transplant: Mar 22 🍅 Harvest: Jun 14 – Nov 1
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 Lamar County

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

Soil pH

Your soil pH (5.8–6.8) overlaps with Rosemary's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is low (1.9%). Add 2-3 inches of compost before planting Rosemary.

How to Plant Rosemary

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

Succession Planting Rosemary

3
successive plantings in your 245-day season

Sow every 9.1 weeks. Last sowing by May 19 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 1.7" 0" ❄️ Dormant
Feb 2.1" 0" ❄️ Dormant
Mar 1.3" 3.5" 0" ✅ Rainfall sufficient
Apr 1.3" 6.8" 0" ✅ Rainfall sufficient
May 1.3" 8.8" 0" ✅ Rainfall sufficient
Jun 1.3" 9.7" 0" ✅ Rainfall sufficient
Jul 1.3" 8" 0" ✅ Rainfall sufficient
Aug 1.3" 7.1" 0" ✅ Rainfall sufficient
Sep 1.3" 5.3" 0" ✅ Rainfall sufficient
Oct 1.3" 3.4" 0" ✅ Rainfall sufficient
Nov 1.3" 2.2" 0" ✅ Rainfall sufficient
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Lamar 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 ~2,372 GDD — county provides 4,471 GDD Excellent fit

Rosemary Planting Timeline — Lamar County, TX

Rosemary Planting Calendar

Activity When Date Range
Transplant Outdoors March 22 Mar 22 – Apr 5
Harvest June 14 Jun 14 – Nov 1

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
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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

245 days in Lamar County

Growing Tips for Rosemary in Lamar County

Direct sow Rosemary outdoors after March 15 in Lamar County when soil has warmed and frost danger has passed.

Sandy soil in Lamar 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 60" of annual rainfall in Lamar 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 Lamar County, TX?

Lamar County is in Zone 8a with an average last frost of March 15. Plan your Rosemary planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lamar County, TX?

Lamar County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 15 and first fall frost is November 15.

🌱

Your Lamar County Garden Planner — Free

A 24-page printable planner built for Lamar 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 Lamar County, TX. 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.