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When to Plant Hyssop in Carroll County, MS

Carroll County, Mississippi Zone 8a May

What to do in May

We've pulled the most time-sensitive tasks for Carroll County, Mississippi this May and put them front and centre. Tackle them in order.

Avg. last frost March 17
Avg. first frost November 9
Soil temp (4") 74°F
Watering Low
Pest pressure High
Daylight 13.7 hrs
June will be here before you know it — start on
  • First harvests: hyssop

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Hyssop is a semi-evergreen perennial herb with intense blue flower spikes that attract bees and butterflies. It has a minty, slightly bitter flavor used in liqueurs and teas.

Carroll County, Mississippi is in USDA Zone 8a. The average last spring frost is March 17 and the first fall frost is November 9, giving you a growing season of approximately 237 days.

At an elevation of 153 feet, Carroll County receives approximately 49.2 inches of rainfall annually with predominantly clay loam soil. Summer highs average 92°F, providing good warmth for Hyssop during the growing season. Clay soil retains moisture well for Hyssop, but amend with compost to improve drainage and prevent root rot.

Carroll County, MS (Zone 8a) Long season
237 days
Last Spring Frost March 17
237 growing days
First Fall Frost November 9
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Carroll County Soil Profile

Soil Type

Clay Loam

Soil pH

5.5-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (98 days to spare)
Transplant: Mar 14 🍅 Harvest: May 23 – Jul 25
Recommended (50%) ✓ Fits season (97 days to spare)
Transplant: Mar 24 🍅 Harvest: Jun 2 – Aug 4
Safe Start (90%) ✓ Fits season (91 days to spare)
Transplant: Apr 16 🍅 Harvest: Jun 25 – Aug 27

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 Carroll County

How your county's soil matches Hyssop's growing requirements.

Soil pH

Your soil pH (5.5–6.7) overlaps with Hyssop's range (6.0–8.0), though not a perfect match.

Soil Texture

The clay loam soil in Carroll County is excellent for Hyssop — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Hyssop.

How to Plant Hyssop

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Hyssop

3
successive plantings in your 237-day season

Sow every 8 weeks. Last sowing by Aug 11 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Hyssop

Hyssop needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Hyssop Needs Rainfall You Supplement Action
Jan 4.2" 0" ❄️ Dormant
Feb 4" 0" ❄️ Dormant
Mar 2.2" 5" 0" ✅ Rainfall sufficient
Apr 2.2" 3.7" 0" ✅ Rainfall sufficient
May 2.2" 4.4" 0" ✅ Rainfall sufficient
Jun 2.2" 4.1" 0" ✅ Rainfall sufficient
Jul 2.2" 4.8" 0" ✅ Rainfall sufficient
Aug 2.2" 4.7" 0" ✅ Rainfall sufficient
Sep 2.2" 3.4" 0" ✅ Rainfall sufficient
Oct 2.2" 3.5" 0" ✅ Rainfall sufficient
Nov 2.2" 3.8" 0" ✅ Rainfall sufficient
Dec 3.7" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Carroll County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Hyssop 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.

Hyssop needs ~1,520 GDD — county provides 4,503 GDD Excellent fit

Hyssop Planting Timeline — Carroll County, MS

Hyssop Planting Calendar

Activity When Date Range
Transplant Outdoors March 24 Mar 24 – Apr 7
Harvest June 2 Jun 2 – Aug 4

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Transplant Outdoors
April Transplant Outdoors
May
June Harvest
July Harvest
August Harvest
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–8 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

237 days in Carroll County

Growing Tips for Hyssop in Carroll County

Direct sow Hyssop outdoors after March 17 in Carroll County when soil has warmed and frost danger has passed.

With Carroll County's clay soil (31% clay), work in 3-4 inches of compost before planting Hyssop. Avoid tilling when soil is wet to prevent compaction.

General growing tips

Start seeds indoors or direct sow in spring. Prune back in early spring to encourage bushy growth. Hyssop is drought-tolerant once established and thrives in poor soil.

Companion Planting

Good Companions

Avoid Planting Near

  • Radish

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Hyssop in Carroll County, MS?

Carroll County is in Zone 8a with an average last frost of March 17. Plan your Hyssop planting based on this frost date — see the calendar above for exact timing.

What planting zone is Carroll County, MS?

Carroll County, Mississippi is in USDA Hardiness Zone 8a. The average last spring frost is March 17 and first fall frost is November 9.

🌱

Your Carroll County Garden Planner — Free

A 24-page printable planner built for Carroll County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Carroll County, MS. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.