When to Plant Rosemary in Hillsborough County, FL
Top priorities for Hillsborough County, Florida gardeners in May
If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.
-
It's harvest week for rosemary
The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.
Looking ahead to June
- 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.
Hillsborough County, Florida is in USDA Zone 10a. The average last spring frost is January 25 and the first fall frost is December 20, giving you a growing season of approximately 329 days.
At an elevation of 63 feet, Hillsborough County receives approximately 54.4 inches of rainfall annually with predominantly sand soil. Summer highs average 98°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. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Rosemary root diseases.
Hillsborough County Soil Profile
Soil Type
Sand
Soil pH
4.9-5.9
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 Hillsborough County
How your county's soil matches Rosemary's growing requirements.
Soil pH
Your soil pH (4.9–5.9) is more acidic than Rosemary prefers (6.0–7.5). Add garden lime to raise pH.
Soil Texture
Sandy soil in Hillsborough County warms quickly in spring but drains fast. Rosemary will need more frequent watering and regular compost additions to retain nutrients.
Drainage
Drainage is adequate for Rosemary.
Organic Matter
Organic matter is low (1.5%). Add 2-3 inches of compost before planting Rosemary.
How to Plant Rosemary
Succession Planting Rosemary
Sow every 9.1 weeks. Last sowing by Jun 23 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 | 1.3" | 2.3" | 0" | ✅ Rainfall sufficient |
| Feb | 1.3" | 2.7" | 0" | ✅ Rainfall sufficient |
| Mar | 1.3" | 2.9" | 0" | ✅ Rainfall sufficient |
| Apr | 1.3" | 2.1" | 0" | ✅ Rainfall sufficient |
| May | 1.3" | 3.8" | 0" | ✅ Rainfall sufficient |
| Jun | 1.3" | 8.1" | 0" | ✅ Rainfall sufficient |
| Jul | 1.3" | 8" | 0" | ✅ Rainfall sufficient |
| Aug | 1.3" | 8" | 0" | ✅ Rainfall sufficient |
| Sep | 1.3" | 7.7" | 0" | ✅ Rainfall sufficient |
| Oct | 1.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Nov | 1.3" | 2" | 0" | ✅ Rainfall sufficient |
| Dec | 1.3" | 2.4" | 0" | ✅ Rainfall sufficient |
Water needs are for active growing months only (Jan–Dec in Hillsborough 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 — Hillsborough County, FL
Rosemary Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | February 1 | Feb 1 – Feb 15 |
| Harvest | April 26 | Apr 26 – Sep 13 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Transplant Outdoors |
| March | — |
| April | Harvest |
| 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: too_acidic
🗺️ USDA Zone
Zone 10a
📆 Growing Season
329 days in Hillsborough County
Growing Tips for Rosemary in Hillsborough County
Direct sow Rosemary outdoors after January 25 in Hillsborough County when soil has warmed and frost danger has passed.
Sandy soil in Hillsborough County dries quickly — mulch Rosemary with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
With summer highs reaching 98°F in Hillsborough County, provide afternoon shade for Rosemary and water deeply in the morning.
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 Hillsborough County, FL?
Hillsborough County is in Zone 10a with an average last frost of January 25. Plan your Rosemary planting based on this frost date — see the calendar above for exact timing.
What planting zone is Hillsborough County, FL?
Hillsborough County, Florida is in USDA Hardiness Zone 10a. The average last spring frost is January 25 and first fall frost is December 20.
Your Hillsborough County Garden Planner — Free
A 24-page printable planner built for Hillsborough 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.