When to Plant Rosemary in St. Mary Parish, LA
St. Mary Parish, Louisiana gardeners: here's your April plan
Your St. Mary Parish, Louisiana garden is entering a new phase. Here's what's on the schedule for April and why each task matters now.
Before May 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.
St. Mary Parish, Louisiana is in USDA Zone 9a. The average last spring frost is February 14 and the first fall frost is December 5, giving you a growing season of approximately 294 days.
At an elevation of 252 feet, St. Mary Parish receives approximately 48.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 95°F, so Rosemary may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Rosemary will need more frequent watering and organic matter to retain nutrients.
St. Mary Parish Soil Profile
Soil Type
Sandy Loam
Soil pH
4.8-6.4
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 St. Mary Parish
How your county's soil matches Rosemary's growing requirements.
Soil pH
Your soil pH (4.8–6.4) is more acidic than Rosemary prefers (6.0–7.5). Add garden lime to raise pH.
Soil Texture
Sandy soil in St. Mary Parish warms quickly in spring but drains fast. Rosemary will need more frequent watering and regular compost additions to retain nutrients.
Drainage
Rosemary prefers dry conditions but your soil drains poorly. Use raised beds or mounded rows to prevent root rot.
Organic Matter
Organic matter is moderate (2.0%). Annual compost additions will help Rosemary.
How to Plant Rosemary
Succession Planting Rosemary
Sow every 9.1 weeks. Last sowing by Jun 08 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 | — | 3.6" | 0" | ❄️ Dormant |
| Feb | 1.3" | 3.4" | 0" | ✅ Rainfall sufficient |
| Mar | 1.3" | 5.1" | 0" | ✅ Rainfall sufficient |
| Apr | 1.3" | 3.8" | 0" | ✅ Rainfall sufficient |
| May | 1.3" | 3.8" | 0" | ✅ Rainfall sufficient |
| Jun | 1.3" | 3.6" | 0" | ✅ Rainfall sufficient |
| Jul | 1.3" | 5.6" | 0" | ✅ Rainfall sufficient |
| Aug | 1.3" | 5.1" | 0" | ✅ Rainfall sufficient |
| Sep | 1.3" | 3.5" | 0" | ✅ Rainfall sufficient |
| Oct | 1.3" | 3.1" | 0" | ✅ Rainfall sufficient |
| Nov | 1.3" | 3.9" | 0" | ✅ Rainfall sufficient |
| Dec | 1.3" | 4.2" | 0" | ✅ Rainfall sufficient |
Water needs are for active growing months only (Feb–Dec in St. Mary Parish). 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 — St. Mary Parish, LA
Rosemary Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | February 21 | Feb 21 – Mar 7 |
| Harvest | May 16 | May 16 – Oct 3 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Transplant Outdoors |
| March | Transplant Outdoors |
| April | — |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| 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: too_acidic
🗺️ USDA Zone
Zone 9a
📆 Growing Season
294 days in St. Mary Parish
Growing Tips for Rosemary in St. Mary Parish
Direct sow Rosemary outdoors after February 14 in St. Mary Parish when soil has warmed and frost danger has passed.
Sandy soil in St. Mary Parish dries quickly — mulch Rosemary with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
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 St. Mary Parish, LA?
St. Mary Parish is in Zone 9a with an average last frost of February 14. Plan your Rosemary planting based on this frost date — see the calendar above for exact timing.
What planting zone is St. Mary Parish, LA?
St. Mary Parish, Louisiana is in USDA Hardiness Zone 9a. The average last spring frost is February 14 and first fall frost is December 5.
Your St. Mary Parish Garden Planner — Free
A 24-page printable planner built for St. Mary Parish (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.