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When to Plant Rosemary in Wharton County, TX

Wharton County, Texas Zone 9a May

What to do in May

May is a pivotal month for Wharton County, Texas gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost February 17
Avg. first frost December 6
Soil temp (4") 76°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Harvest rosemary as they ripen

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

June will be here before you know it — start on
  • 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.

Wharton County, Texas is in USDA Zone 9a. The average last spring frost is February 17 and the first fall frost is December 6, giving you a growing season of approximately 292 days.

At an elevation of 207 feet, Wharton County receives approximately 64.8 inches of rainfall annually with predominantly loam soil. Summer highs average 98°F, so Rosemary may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Rosemary root diseases.

Wharton County, TX (Zone 9a) Year-round
292 days
Last Spring Frost February 17
292 growing days
First Fall Frost December 6
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Wharton County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (64 days to spare)
Transplant: Feb 12 🍅 Harvest: May 7 – Sep 24
Recommended (50%) ✓ Fits season (61 days to spare)
Transplant: Feb 24 🍅 Harvest: May 19 – Oct 6
Safe Start (90%) ✓ Fits season (53 days to spare)
Transplant: Mar 19 🍅 Harvest: Jun 11 – Oct 29

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 Wharton County

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

Soil pH

Your soil pH (6.6–7.7) overlaps with Rosemary's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Wharton 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

4
successive plantings in your 292-day season

Sow every 9.1 weeks. Last sowing by Jun 09 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 1.7" 0" ❄️ Dormant
Feb 1.3" 2.2" 0" ✅ Rainfall sufficient
Mar 1.3" 4.6" 0" ✅ Rainfall sufficient
Apr 1.3" 6.6" 0" ✅ Rainfall sufficient
May 1.3" 9" 0" ✅ Rainfall sufficient
Jun 1.3" 10.4" 0" ✅ Rainfall sufficient
Jul 1.3" 8.4" 0" ✅ Rainfall sufficient
Aug 1.3" 7.4" 0" ✅ Rainfall sufficient
Sep 1.3" 5.7" 0" ✅ Rainfall sufficient
Oct 1.3" 4.4" 0" ✅ Rainfall sufficient
Nov 1.3" 2.4" 0" ✅ Rainfall sufficient
Dec 1.3" 1.9" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Feb–Dec in Wharton 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 ~3,055 GDD — county provides 6,885 GDD Excellent fit

Rosemary Planting Timeline — Wharton County, TX

Rosemary Planting Calendar

Activity When Date Range
Transplant Outdoors February 24 Feb 24 – Mar 10
Harvest May 19 May 19 – Oct 6

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

Month-by-Month Timeline

MonthActivities
January
February Transplant Outdoors
March Transplant Outdoors
April
May Harvest
June Harvest
July Harvest
August Harvest
September Harvest
October Harvest
November
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 9a

📆 Growing Season

292 days in Wharton County

Growing Tips for Rosemary in Wharton County

Direct sow Rosemary outdoors after February 17 in Wharton County when soil has warmed and frost danger has passed.

With summer highs reaching 98°F in Wharton County, provide afternoon shade for Rosemary and water deeply in the morning.

With 65" of annual rainfall in Wharton 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 Wharton County, TX?

Wharton County is in Zone 9a with an average last frost of February 17. Plan your Rosemary planting based on this frost date — see the calendar above for exact timing.

What planting zone is Wharton County, TX?

Wharton County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 17 and first fall frost is December 6.

🌱

Your Wharton County Garden Planner — Free

A 24-page printable planner built for Wharton 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.

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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 Wharton 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.