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When to Plant Rosemary in Kerr County, TX

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.

Kerr County, Texas is in USDA Zone 8a. The average last spring frost is March 24 and the first fall frost is November 11, giving you a growing season of approximately 232 days.

At an elevation of 3,907 feet, Kerr County receives approximately 52 inches of rainfall annually with predominantly loam soil. Summer highs average 93ยฐF, providing good warmth for Rosemary during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Rosemary root diseases.

Kerr County, TX (Zone 8a) Long season
232 days
Last Spring Frost March 24
232 growing days
First Fall Frost November 11

Kerr County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (2 days to spare)
Transplant: Mar 19 🍅 Harvest: Jun 11 – Oct 29
Recommended (50%) ✓ Fits season (1 days to spare)
Transplant: Mar 31 🍅 Harvest: Jun 23 – Nov 10
Safe Start (90%) ✗ May not fit
Transplant: Apr 23 🍅 Harvest: Jul 16 – Dec 3

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 Kerr County

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

Soil pH

Your soil pH (6.4โ€“7.6) overlaps with Rosemary's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

The loam soil in Kerr County is excellent for Rosemary โ€” good drainage, moisture retention, and nutrient holding capacity.

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 232-day season

Sow every 9.1 weeks. Last sowing by May 15 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 โ€” 1.2" 0" โ„๏ธ Dormant
Feb โ€” 1.6" 0" โ„๏ธ Dormant
Mar 1.3" 3.4" 0" โœ… Rainfall sufficient
Apr 1.3" 5.7" 0" โœ… Rainfall sufficient
May 1.3" 6.7" 0" โœ… Rainfall sufficient
Jun 1.3" 9.2" 0" โœ… Rainfall sufficient
Jul 1.3" 7.3" 0" โœ… Rainfall sufficient
Aug 1.3" 6.1" 0" โœ… Rainfall sufficient
Sep 1.3" 4.8" 0" โœ… Rainfall sufficient
Oct 1.3" 3.1" 0" โœ… Rainfall sufficient
Nov 1.3" 1.7" 0" โœ… Rainfall sufficient
Dec โ€” 1.3" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Nov in Kerr County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~2,568 GDD — county provides 4,582 GDD Excellent fit

Rosemary Planting Timeline โ€” Kerr County, TX

Rosemary Planting Calendar

Activity When Date Range
Transplant Outdoors March 31 Mar 31 โ€“ Apr 14
Harvest June 23 Jun 23 โ€“ Nov 10

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.3"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

80โ€“180 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 8a

๐Ÿ“† Growing Season

232 days in Kerr County

Growing Tips for Rosemary in Kerr County

Direct sow Rosemary outdoors after March 24 in Kerr County when soil has warmed and frost danger has passed.

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 Kerr County, TX?

Kerr County is in Zone 8a with an average last frost of March 24. Plan your Rosemary planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Kerr County, TX?

Kerr County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 24 and first fall frost is November 11.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Kerr County gardeners in Zone 8a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Kerr County, TX. Local conditions may vary. Last updated: April 2026.