When to Plant Rosemary in Cameron County, TX
Your May gardening checklist
Here's what deserves your attention in Cameron County, Texas this month. Everything below is tailored to Zone 10a and timed around your local frost dates.
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Harvest rosemary as they ripen
The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.
Before June arrives, get these ready
- First harvests: rosemary
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.
Cameron County, Texas is in USDA Zone 10a. The average last spring frost is February 4 and the first fall frost is December 22, giving you a growing season of approximately 321 days.
At an elevation of 4,025 feet, Cameron County receives approximately 58.6 inches of rainfall annually with predominantly loam soil. Summer highs average 103°F, so Rosemary may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Rosemary root diseases.
Cameron County Soil Profile
Soil Type
Loam
Soil pH
6.7-7.8
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 Cameron County
How your county's soil matches Rosemary's growing requirements.
Soil pH
Your soil pH (6.7–7.8) overlaps with Rosemary's range (6.0–7.5), though not a perfect match.
Soil Texture
The loam soil in Cameron County is excellent for Rosemary — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.2%). Annual compost additions will help Rosemary.
How to Plant Rosemary
Succession Planting Rosemary
Sow every 9.1 weeks. Last sowing by Jun 25 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 | — | 1.6" | 0" | ❄️ Dormant |
| Feb | 1.3" | 2.2" | 0" | ✅ Rainfall sufficient |
| Mar | 1.3" | 3.1" | 0" | ✅ Rainfall sufficient |
| Apr | 1.3" | 6.1" | 0" | ✅ Rainfall sufficient |
| May | 1.3" | 9.2" | 0" | ✅ Rainfall sufficient |
| Jun | 1.3" | 9.1" | 0" | ✅ Rainfall sufficient |
| Jul | 1.3" | 7.5" | 0" | ✅ Rainfall sufficient |
| Aug | 1.3" | 6.9" | 0" | ✅ Rainfall sufficient |
| Sep | 1.3" | 5.6" | 0" | ✅ Rainfall sufficient |
| Oct | 1.3" | 3.8" | 0" | ✅ Rainfall sufficient |
| Nov | 1.3" | 2.1" | 0" | ✅ Rainfall sufficient |
| Dec | 1.3" | 1.4" | 0" | ✅ Rainfall sufficient |
Water needs are for active growing months only (Feb–Dec in Cameron 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 — Cameron County, TX
Rosemary Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | February 11 | Feb 11 – Feb 25 |
| Harvest | May 6 | May 6 – Sep 23 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Transplant Outdoors |
| March | — |
| April | — |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| 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 10a
📆 Growing Season
321 days in Cameron County
Growing Tips for Rosemary in Cameron County
Direct sow Rosemary outdoors after February 04 in Cameron County when soil has warmed and frost danger has passed.
With summer highs reaching 103°F in Cameron County, provide afternoon shade for Rosemary and water deeply in the morning.
With 59" of annual rainfall in Cameron 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 →
Rosemary in Other Locations
Frequently Asked Questions
When should I plant Rosemary in Cameron County, TX?
Cameron County is in Zone 10a with an average last frost of February 4. Plan your Rosemary planting based on this frost date — see the calendar above for exact timing.
What planting zone is Cameron County, TX?
Cameron County, Texas is in USDA Hardiness Zone 10a. The average last spring frost is February 4 and first fall frost is December 22.
Your Cameron County Garden Planner — Free
A 24-page printable planner built for Cameron County (Zone 10a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.