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When to Plant Rosemary in Ottawa County, OK

Ottawa County, Oklahoma Zone 7a May

Your May planting checklist for Ottawa County, Oklahoma

Here's what deserves your attention in Ottawa County, Oklahoma this month. Everything below is tailored to Zone 7a and timed around your local frost dates.

Avg. last frost April 9
Avg. first frost October 26
Soil temp (4") 69°F
Watering Low
Pest pressure Moderate
Daylight 14 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.

Ottawa County, Oklahoma is in USDA Zone 7a. The average last spring frost is April 9 and the first fall frost is October 26, giving you a growing season of approximately 200 days.

At an elevation of 716 feet, Ottawa County receives approximately 29.5 inches of rainfall annually with predominantly loam soil. Summer highs average 93°F, providing good warmth for Rosemary during the growing season.

Ottawa County, OK (Zone 7a) Long season
200 days
Last Spring Frost April 9
200 growing days
First Fall Frost October 26

Ottawa County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 10 🍅 Harvest: Jul 3 – Nov 20
Recommended (50%) ✗ May not fit
Transplant: Apr 16 🍅 Harvest: Jul 9 – Nov 26
Safe Start (90%) ✗ May not fit
Transplant: Apr 30 🍅 Harvest: Jul 23 – Dec 10

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 Ottawa County

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

Soil pH

Your soil pH (6.8–7.8) overlaps with Rosemary's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Ottawa County is excellent for Rosemary — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.3%) — Rosemary will thrive.

How to Plant Rosemary

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

Succession Planting Rosemary

2
successive plantings in your 200-day season

Sow every 9.1 weeks. Last sowing by Apr 29 to harvest before frost.

Plant Water Budget

Plant needs
0.3″/week
Rainfall provides
0.6″/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 0.8" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 1.3" 2.9" 0" ✅ Rainfall sufficient
May 1.3" 4.6" 0" ✅ Rainfall sufficient
Jun 1.3" 4.7" 0" ✅ Rainfall sufficient
Jul 1.3" 3.5" 0" ✅ Rainfall sufficient
Aug 1.3" 3.6" 0" ✅ Rainfall sufficient
Sep 1.3" 2.8" 0" ✅ Rainfall sufficient
Oct 1.3" 1.9" 0" ✅ Rainfall sufficient
Nov 0.9" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Ottawa 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 ~2,568 GDD — county provides 3,950 GDD Excellent fit

Rosemary Planting Timeline — Ottawa County, OK

Rosemary Planting Calendar

Activity When Date Range
Transplant Outdoors April 16 Apr 16 – Apr 30
Harvest July 9 Jul 9 – Nov 26

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Transplant Outdoors
May
June
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 7a

📆 Growing Season

200 days in Ottawa County

Growing Tips for Rosemary in Ottawa County

Direct sow Rosemary outdoors after April 09 in Ottawa 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 Ottawa County, OK?

Ottawa County is in Zone 7a with an average last frost of April 9. Plan your Rosemary planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ottawa County, OK?

Ottawa County, Oklahoma is in USDA Hardiness Zone 7a. The average last spring frost is April 9 and first fall frost is October 26.

🌱

Your Ottawa County Garden Planner — Free

A 24-page printable planner built for Ottawa 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Ottawa County, OK. 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.