When to Plant Rosemary in Marshall County, OK
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.
Marshall County, Oklahoma is in USDA Zone 7b. The average last spring frost is March 24 and the first fall frost is November 12, giving you a growing season of approximately 233 days.
At an elevation of 520 feet, Marshall County receives approximately 23.7 inches of rainfall annually with predominantly loam soil. Summer highs average 92°F, providing good warmth for Rosemary during the growing season.
Marshall County Soil Profile
Soil Type
Loam
Soil pH
6.2-7.8
Drainage
Well Drained
Plant Planting Risk Windows
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 Marshall County
How your county's soil matches Rosemary's growing requirements.
Soil pH
Your soil pH (6.2–7.8) overlaps with Rosemary's range (6.0–7.5), though not a perfect match.
Soil Texture
The loam soil in Marshall County is excellent for Rosemary — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Rosemary.
Organic Matter
Organic matter is moderate (3.5%). Annual compost additions will help Rosemary.
How to Plant Rosemary
Succession Planting Rosemary
Sow every 9.1 weeks. Last sowing by May 16 to harvest before frost.
Plant Water Budget
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 | — | 0.5" | 0" | ❄️ Dormant |
| Feb | — | 0.8" | 0" | ❄️ Dormant |
| Mar | 1.3" | 1.6" | 0" | ✅ Rainfall sufficient |
| Apr | 1.3" | 2.3" | 0" | ✅ Rainfall sufficient |
| May | 1.3" | 4" | 0" | ✅ Rainfall sufficient |
| Jun | 1.3" | 3.4" | 0" | ✅ Rainfall sufficient |
| Jul | 1.3" | 3" | 0" | ✅ Rainfall sufficient |
| Aug | 1.3" | 2.8" | 0" | ✅ Rainfall sufficient |
| Sep | 1.3" | 2.4" | 0" | ✅ Rainfall sufficient |
| Oct | 1.3" | 1.3" | 0" | ✅ Rainfall sufficient |
| Nov | 1.3" | 0.9" | 0.4" | 💧 Light watering |
| Dec | — | 0.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Marshall 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 Planting Timeline — Marshall County, OK
Rosemary Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | March 31 | Mar 31 – Apr 14 |
| Harvest | June 23 | Jun 23 – Nov 10 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Transplant Outdoors |
| April | Transplant Outdoors |
| May | — |
| June | Harvest |
| 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 7b
📆 Growing Season
233 days in Marshall County
Growing Tips for Rosemary in Marshall County
Direct sow Rosemary outdoors after March 24 in Marshall 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 →
Rosemary in Other Locations
Frequently Asked Questions
When should I plant Rosemary in Marshall County, OK?
Marshall County is in Zone 7b with an average last frost of March 24. Plan your Rosemary planting based on this frost date — see the calendar above for exact timing.
What planting zone is Marshall County, OK?
Marshall County, Oklahoma is in USDA Hardiness Zone 7b. The average last spring frost is March 24 and first fall frost is November 12.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Marshall County gardeners in Zone 7b organize planting dates, track what's growing, and never miss a planting window.
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