When to Plant Rosemary in Union Parish, LA
What to do in May
Welcome to May in Zone 8b. These are the moves that will have the biggest impact on your growing season.
June prep starts now
- 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.
Union Parish, Louisiana is in USDA Zone 8b. The average last spring frost is March 22 and the first fall frost is November 5, giving you a growing season of approximately 228 days.
At an elevation of 426 feet, Union Parish receives approximately 57.4 inches of rainfall annually with predominantly loam soil. Summer highs average 96°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.
Union Parish Soil Profile
Soil Type
Loam
Soil pH
5.9-7
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 Union Parish
How your county's soil matches Rosemary's growing requirements.
Soil pH
Your soil pH (5.9–7.0) overlaps with Rosemary's range (6.0–7.5), though not a perfect match.
Soil Texture
The loam soil in Union Parish is excellent for Rosemary — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.9%). Annual compost additions will help Rosemary.
How to Plant Rosemary
Succession Planting Rosemary
Sow every 9.1 weeks. Last sowing by May 09 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 | — | 4.6" | 0" | ❄️ Dormant |
| Feb | — | 4.7" | 0" | ❄️ Dormant |
| Mar | 1.3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Apr | 1.3" | 4.1" | 0" | ✅ Rainfall sufficient |
| May | 1.3" | 5.2" | 0" | ✅ Rainfall sufficient |
| Jun | 1.3" | 5.3" | 0" | ✅ Rainfall sufficient |
| Jul | 1.3" | 6.1" | 0" | ✅ Rainfall sufficient |
| Aug | 1.3" | 5.4" | 0" | ✅ Rainfall sufficient |
| Sep | 1.3" | 5" | 0" | ✅ Rainfall sufficient |
| Oct | 1.3" | 3.9" | 0" | ✅ Rainfall sufficient |
| Nov | 1.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Dec | — | 3.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Union 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 — Union Parish, LA
Rosemary Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | March 29 | Mar 29 – Apr 12 |
| Harvest | June 21 | Jun 21 – Nov 8 |
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 8b
📆 Growing Season
228 days in Union Parish
Growing Tips for Rosemary in Union Parish
Direct sow Rosemary outdoors after March 22 in Union Parish when soil has warmed and frost danger has passed.
With summer highs reaching 96°F in Union Parish, provide afternoon shade for Rosemary and water deeply in the morning.
With 57" of annual rainfall in Union Parish, 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 Union Parish, LA?
Union Parish is in Zone 8b with an average last frost of March 22. Plan your Rosemary planting based on this frost date — see the calendar above for exact timing.
What planting zone is Union Parish, LA?
Union Parish, Louisiana is in USDA Hardiness Zone 8b. The average last spring frost is March 22 and first fall frost is November 5.
Your Union Parish Garden Planner — Free
A 24-page printable planner built for Union Parish (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.