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When to Plant Hyssop in Robeson County, NC

Robeson County, North Carolina Zone 8b May

Your May game plan for Robeson County, North Carolina

Each item below is timed to Robeson County, North Carolina's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost March 24
Avg. first frost November 6
Soil temp (4") 71°F
Watering Moderate
Pest pressure High
Daylight 13.8 hrs
Get ahead of 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.

Robeson County, North Carolina is in USDA Zone 8b. The average last spring frost is March 24 and the first fall frost is November 6, giving you a growing season of approximately 227 days.

At an elevation of 887 feet, Robeson County receives approximately 49.7 inches of rainfall annually with predominantly clay loam soil. Summer highs average 97°F, so Hyssop may need afternoon shade and extra watering during peak heat. Clay soil retains moisture well for Hyssop, but amend with compost to improve drainage and prevent root rot.

Robeson County, NC (Zone 8b) Long season
227 days
Last Spring Frost March 24
227 growing days
First Fall Frost November 6

Robeson County Soil Profile

Soil Type

Clay Loam

Soil pH

5.3-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (90 days to spare)
Transplant: Mar 23 🍅 Harvest: Jun 1 – Aug 3
Recommended (50%) ✓ Fits season (87 days to spare)
Transplant: Mar 31 🍅 Harvest: Jun 9 – Aug 11
Safe Start (90%) ✓ Fits season (81 days to spare)
Transplant: Apr 23 🍅 Harvest: Jul 2 – Sep 3

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 Robeson County

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

Soil pH

Your soil pH (5.3–6.2) is more acidic than Hyssop prefers (6.0–8.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). 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 227-day season

Sow every 8 weeks. Last sowing by Aug 08 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 3.7" 0" ❄️ Dormant
Feb 4.1" 0" ❄️ Dormant
Mar 2.2" 4.9" 0" ✅ Rainfall sufficient
Apr 2.2" 3.8" 0" ✅ Rainfall sufficient
May 2.2" 3.6" 0" ✅ Rainfall sufficient
Jun 2.2" 4.9" 0" ✅ Rainfall sufficient
Jul 2.2" 5" 0" ✅ Rainfall sufficient
Aug 2.2" 5.3" 0" ✅ Rainfall sufficient
Sep 2.2" 3.9" 0" ✅ Rainfall sufficient
Oct 2.2" 2.9" 0" ✅ Rainfall sufficient
Nov 2.2" 3.3" 0" ✅ Rainfall sufficient
Dec 4.4" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Robeson 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 ~1,820 GDD — county provides 5,164 GDD Excellent fit

Hyssop Planting Timeline — Robeson County, NC

Hyssop Planting Calendar

Activity When Date Range
Transplant Outdoors March 31 Mar 31 – Apr 14
Harvest June 9 Jun 9 – Aug 11

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

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: too_acidic

🗺️ USDA Zone

Zone 8b

📆 Growing Season

227 days in Robeson County

Growing Tips for Hyssop in Robeson County

Direct sow Hyssop outdoors after March 24 in Robeson County when soil has warmed and frost danger has passed.

With Robeson 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.

With summer highs reaching 97°F in Robeson County, provide afternoon shade for Hyssop and water deeply in the morning.

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 Robeson County, NC?

Robeson County is in Zone 8b with an average last frost of March 24. Plan your Hyssop planting based on this frost date — see the calendar above for exact timing.

What planting zone is Robeson County, NC?

Robeson County, North Carolina is in USDA Hardiness Zone 8b. The average last spring frost is March 24 and first fall frost is November 6.

🌱

Your Robeson County Garden Planner — Free

A 24-page printable planner built for Robeson County (Zone 8b). 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 Robeson County, NC. 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.