When to Plant Rosemary in Mariposa County, CA
May in Mariposa County, California — your action list
May is a pivotal month for Mariposa County, California gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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.
Mariposa County, California is in USDA Zone 9b. The average last spring frost is April 18 and the first fall frost is November 9, giving you a growing season of approximately 205 days.
At an elevation of 192 feet, Mariposa County receives approximately 19.2 inches of rainfall annually with predominantly loam soil. Summer highs average 91°F, providing good warmth for Rosemary during the growing season. With low rainfall, drip irrigation is essential for growing Rosemary successfully. Mulch heavily to conserve soil moisture.
Mariposa County Soil Profile
Soil Type
Loam
Soil pH
6.5-7.5
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 Mariposa County
How your county's soil matches Rosemary's growing requirements.
Soil pH
Your soil pH (6.5–7.5) is within Rosemary's preferred range (6.0–7.5).
Soil Texture
The loam soil in Mariposa County is excellent for Rosemary — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.8%). Annual compost additions will help Rosemary.
How to Plant Rosemary
Succession Planting Rosemary
Sow every 9.1 weeks. Last sowing by May 13 to harvest before frost.
Plant Water Budget
Water stress score is 8/10 — 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 | — | 3.7" | 0" | ❄️ Dormant |
| Feb | — | 4.3" | 0" | ❄️ Dormant |
| Mar | — | 3.2" | 0" | ❄️ Dormant |
| Apr | 1.3" | 1.6" | 0" | ✅ Rainfall sufficient |
| May | 1.3" | 0.5" | 0.8" | 🚿 Regular watering |
| Jun | 1.3" | 0.1" | 1.2" | 🚿 Regular watering |
| Jul | 1.3" | 0" | 1.3" | 🚿 Regular watering |
| Aug | 1.3" | 0" | 1.3" | 🚿 Regular watering |
| Sep | 1.3" | 0.2" | 1.1" | 🚿 Regular watering |
| Oct | 1.3" | 0.9" | 0.4" | 💧 Light watering |
| Nov | 1.3" | 1.9" | 0" | ✅ Rainfall sufficient |
| Dec | — | 2.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Nov in Mariposa 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 — Mariposa County, CA
Rosemary Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 25 | Apr 25 – May 9 |
| Harvest | July 18 | Jul 18 – Dec 5 |
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 | Harvest |
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: ideal
🗺️ USDA Zone
Zone 9b
📆 Growing Season
205 days in Mariposa County
Growing Tips for Rosemary in Mariposa County
Direct sow Rosemary outdoors after April 18 in Mariposa 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 Mariposa County, CA?
Mariposa County is in Zone 9b with an average last frost of April 18. Plan your Rosemary planting based on this frost date — see the calendar above for exact timing.
What planting zone is Mariposa County, CA?
Mariposa County, California is in USDA Hardiness Zone 9b. The average last spring frost is April 18 and first fall frost is November 9.
Your Mariposa County Garden Planner — Free
A 24-page printable planner built for Mariposa County (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.