When to Plant Rosemary in Clatsop County, OR
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.
Clatsop County, Oregon is in USDA Zone 8b. The average last spring frost is April 12 and the first fall frost is November 4, giving you a growing season of approximately 206 days.
At an elevation of 412 feet, Clatsop County receives approximately 54.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Rosemary during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Rosemary root diseases.
Clatsop County Soil Profile
Soil Type
Silt Loam
Soil pH
5.6-6.7
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 Clatsop County
How your county's soil matches Rosemary's growing requirements.
Soil pH
Your soil pH (5.6–6.7) overlaps with Rosemary's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Clatsop County is excellent for Rosemary — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.9%) — Rosemary will thrive.
How to Plant Rosemary
Succession Planting Rosemary
Sow every 9.1 weeks. Last sowing by May 08 to harvest before frost.
Plant Water Budget
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 | — | 8.4" | 0" | ❄️ Dormant |
| Feb | — | 5.2" | 0" | ❄️ Dormant |
| Mar | — | 4.8" | 0" | ❄️ Dormant |
| Apr | 1.3" | 3.8" | 0" | ✅ Rainfall sufficient |
| May | 1.3" | 3.6" | 0" | ✅ Rainfall sufficient |
| Jun | 1.3" | 2.1" | 0" | ✅ Rainfall sufficient |
| Jul | 1.3" | 0.9" | 0.4" | 💧 Light watering |
| Aug | 1.3" | 1.1" | 0.2" | 💧 Light watering |
| Sep | 1.3" | 2.4" | 0" | ✅ Rainfall sufficient |
| Oct | 1.3" | 4.2" | 0" | ✅ Rainfall sufficient |
| Nov | 1.3" | 8.4" | 0" | ✅ Rainfall sufficient |
| Dec | — | 9.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Nov in Clatsop 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 — Clatsop County, OR
Rosemary Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 19 | Apr 19 – May 3 |
| Harvest | July 12 | Jul 12 – Nov 29 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Transplant Outdoors |
| May | Transplant Outdoors |
| 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 8b
📆 Growing Season
206 days in Clatsop County
Growing Tips for Rosemary in Clatsop County
Direct sow Rosemary outdoors after April 12 in Clatsop 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 Clatsop County, OR?
Clatsop County is in Zone 8b with an average last frost of April 12. Plan your Rosemary planting based on this frost date — see the calendar above for exact timing.
What planting zone is Clatsop County, OR?
Clatsop County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is April 12 and first fall frost is November 4.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Clatsop County gardeners in Zone 8b organize planting dates, track what's growing, and never miss a planting window.
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