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When to Plant Hyssop in Iredell County, NC

Iredell County, North Carolina Zone 7b May

Your May planting checklist for Iredell County, North Carolina

A quick May briefing for Iredell County, North Carolina gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 7
Avg. first frost November 1
Soil temp (4") 69°F
Watering Low
Pest pressure Moderate
Daylight 13.9 hrs
A few tasks this May that'll pay off in June
  • 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.

Iredell County, North Carolina is in USDA Zone 7b. The average last spring frost is April 7 and the first fall frost is November 1, giving you a growing season of approximately 208 days.

At an elevation of 400 feet, Iredell County receives approximately 44.9 inches of rainfall annually with predominantly clay loam soil. Summer highs average 91°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.

Iredell County, NC (Zone 7b) Long season
208 days
Last Spring Frost April 7
208 growing days
First Fall Frost November 1
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Iredell 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 (73 days to spare)
Transplant: Apr 1 🍅 Harvest: Jun 10 – Aug 12
Recommended (50%) ✓ Fits season (68 days to spare)
Transplant: Apr 14 🍅 Harvest: Jun 23 – Aug 25
Safe Start (90%) ✓ Fits season (67 days to spare)
Transplant: Apr 28 🍅 Harvest: Jul 7 – Sep 8

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 Iredell 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 Iredell County is excellent for Hyssop — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). 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 208-day season

Sow every 8 weeks. Last sowing by Aug 03 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
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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" 0" ❄️ Dormant
Feb 3.8" 0" ❄️ Dormant
Mar 3.9" 0" ❄️ Dormant
Apr 2.2" 3.3" 0" ✅ Rainfall sufficient
May 2.2" 4" 0" ✅ Rainfall sufficient
Jun 2.2" 4.2" 0" ✅ Rainfall sufficient
Jul 2.2" 4.1" 0" ✅ Rainfall sufficient
Aug 2.2" 4.4" 0" ✅ Rainfall sufficient
Sep 2.2" 3.9" 0" ✅ Rainfall sufficient
Oct 2.2" 2.7" 0" ✅ Rainfall sufficient
Nov 2.2" 3.3" 0" ✅ Rainfall sufficient
Dec 3.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Iredell 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 ~1,460 GDD — county provides 3,796 GDD Excellent fit

Hyssop Planting Timeline — Iredell County, NC

Hyssop Planting Calendar

Activity When Date Range
Transplant Outdoors April 14 Apr 14 – Apr 28
Harvest June 23 Jun 23 – Aug 25

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

Month-by-Month Timeline

MonthActivities
January
February
March
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 7b

📆 Growing Season

208 days in Iredell County

Growing Tips for Hyssop in Iredell County

Direct sow Hyssop outdoors after April 07 in Iredell County when soil has warmed and frost danger has passed.

With Iredell County's clay soil (30% 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 Iredell County, NC?

Iredell County is in Zone 7b with an average last frost of April 7. Plan your Hyssop planting based on this frost date — see the calendar above for exact timing.

What planting zone is Iredell County, NC?

Iredell County, North Carolina is in USDA Hardiness Zone 7b. The average last spring frost is April 7 and first fall frost is November 1.

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Your Iredell County Garden Planner — Free

A 24-page printable planner built for Iredell County (Zone 7b). 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 Iredell County, NC. Local conditions may vary. Last updated: May 2026.

Sources & credits

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