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When to Plant Rosemary in Armstrong County, TX

Armstrong County, Texas Zone 7a May

Your May planting checklist for Armstrong County, Texas

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

Avg. last frost April 15
Avg. first frost October 24
Soil temp (4") 63°F
Watering High
Pest pressure Moderate
Daylight 13.8 hrs

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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.

Armstrong County, Texas is in USDA Zone 7a. The average last spring frost is April 15 and the first fall frost is October 24, giving you a growing season of approximately 192 days.

At an elevation of 2,506 feet, Armstrong County receives approximately 57.6 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 102°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. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Rosemary root diseases.

Armstrong County, TX (Zone 7a) Moderate season
192 days
Last Spring Frost April 15
192 growing days
First Fall Frost October 24
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Armstrong County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.2-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 18 🍅 Harvest: Jul 11 – Nov 28
Recommended (50%) ✗ May not fit
Transplant: Apr 22 🍅 Harvest: Jul 15 – Dec 2
Safe Start (90%) ✗ May not fit
Transplant: May 8 🍅 Harvest: Jul 31 – Dec 18

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 Armstrong County

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

Soil pH

Your soil pH (7.2–8.3) is more alkaline than Rosemary prefers (6.0–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Armstrong 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 (0.9%). 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

2
successive plantings in your 192-day season

Sow every 9.1 weeks. Last sowing by Apr 27 to harvest before frost.

Plant Water Budget

Plant needs
0.3″/week
Rainfall provides
1.3″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 3.6" 0" ❄️ Dormant
Feb 3.6" 0" ❄️ Dormant
Mar 3" 0" ❄️ Dormant
Apr 1.3" 2.2" 0" ✅ Rainfall sufficient
May 1.3" 1.4" 0" ✅ Rainfall sufficient
Jun 1.3" 1.9" 0" ✅ Rainfall sufficient
Jul 1.3" 8.8" 0" ✅ Rainfall sufficient
Aug 1.3" 13.9" 0" ✅ Rainfall sufficient
Sep 1.3" 6.9" 0" ✅ Rainfall sufficient
Oct 1.3" 5" 0" ✅ Rainfall sufficient
Nov 3.2" 0" ❄️ Dormant
Dec 4.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Armstrong 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 ~3,445 GDD — county provides 5,088 GDD Excellent fit

Rosemary Planting Timeline — Armstrong County, TX

Rosemary Planting Calendar

Activity When Date Range
Transplant Outdoors April 22 Apr 22 – May 6
Harvest July 15 Jul 15 – Dec 2

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Transplant Outdoors
May Transplant Outdoors
June
July Harvest
August Harvest
September Harvest
October Harvest
November Harvest
December Harvest
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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: too_alkaline

🗺️ USDA Zone

Zone 7a

📆 Growing Season

192 days in Armstrong County

Growing Tips for Rosemary in Armstrong County

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

Sandy soil in Armstrong 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 102°F in Armstrong County, provide afternoon shade for Rosemary and water deeply in the morning.

Your 192.0-day growing season in Armstrong County is tight for Rosemary (80.0-180.0 days to maturity). Start indoors and choose early-maturing varieties.

With 58" of annual rainfall in Armstrong 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 Armstrong County, TX?

Armstrong County is in Zone 7a with an average last frost of April 15. Plan your Rosemary planting based on this frost date — see the calendar above for exact timing.

What planting zone is Armstrong County, TX?

Armstrong County, Texas is in USDA Hardiness Zone 7a. The average last spring frost is April 15 and first fall frost is October 24.

🌱

Your Armstrong County Garden Planner — Free

A 24-page printable planner built for Armstrong County (Zone 7a). 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 Armstrong 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.