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When to plant Hyssop in Johnson County, MO

Johnson County sits in cold Zone 6b. Plant Hyssop April 20–May 4 for the single annual harvest; the October 23 first frost closes the window.

When to Plant Hyssop in Johnson County, MO

Johnson County, Missouri Zone 6b July

July in Johnson County, Missouri — your action list

If you only do a handful of things in the garden this July, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 13
Avg. first frost October 23
Soil temp (4") 79°F
Watering Low
Pest pressure High
Daylight 14.5 hrs
  1. Pick hyssop

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

August 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.

Johnson County, Missouri is in USDA Zone 6b. The average last spring frost is April 13 and the first fall frost is October 23, giving you a growing season of approximately 193 days.

At an elevation of 1,218 feet, Johnson County receives approximately 41 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Hyssop during the growing season.

Johnson County, MO (Zone 6b) Moderate season
193 days
Last Spring Frost April 13
193 growing days
First Fall Frost October 23

Johnson County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.5

Drainage

Well Drained

Hyssop Planting Risk Windows

Early Start (70% safe) ✓ Fits season (54 days to spare)
Transplant: Apr 12 🍅 Harvest: Jun 21 – Aug 23
Recommended (50%) ✓ Fits season (53 days to spare)
Transplant: Apr 20 🍅 Harvest: Jun 29 – Aug 31
Safe Start (90%) ✓ Fits season (54 days to spare)
Transplant: May 2 🍅 Harvest: Jul 11 – Sep 12

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 Johnson County

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

Soil pH

Your soil pH (5.3–6.5) is more acidic than Hyssop prefers (6.0–8.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.0%). 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 193-day season

Sow every 8 weeks. Last sowing by Jul 25 to harvest before frost.

Hyssop 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 1.5" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 2.2" 3.6" 0" ✅ Rainfall sufficient
May 2.2" 4.5" 0" ✅ Rainfall sufficient
Jun 2.2" 5.8" 0" ✅ Rainfall sufficient
Jul 2.2" 4.1" 0" ✅ Rainfall sufficient
Aug 2.2" 4.9" 0" ✅ Rainfall sufficient
Sep 2.2" 3.8" 0" ✅ Rainfall sufficient
Oct 2.2" 3" 0" ✅ Rainfall sufficient
Nov 2.8" 0" ❄️ Dormant
Dec 2.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Johnson 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 ~1,160 GDD — county provides 2,798 GDD Excellent fit

Hyssop Planting Timeline — Johnson County, MO

Hyssop Planting Calendar

Activity When Date Range
Transplant Outdoors April 20 Apr 20 – May 4
Harvest June 29 Jun 29 – Aug 31

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Transplant Outdoors
May Transplant Outdoors
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 6b

📆 Growing Season

193 days in Johnson County

Growing Tips for Hyssop in Johnson County

Direct sow Hyssop outdoors after April 13 in Johnson County when soil has warmed and frost danger has passed.

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 Johnson County, MO?

Johnson County is in Zone 6b with an average last frost of April 13. Plan your Hyssop planting based on this frost date — see the calendar above for exact timing.

What planting zone is Johnson County, MO?

Johnson County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 13 and first fall frost is October 23.

When should I plant Hyssop in Johnson County, MO?

In Johnson County, MO, plant Hyssop after the last frost (around April 13) and before the first frost (around October 23). Best results when soil holds above 50°F.

What growing zone is Johnson County, MO for Hyssop?

Johnson County sits in USDA Zone 6b. Hyssop grows reliably in zones 3a through 9b, so it's a good fit here.

Can Hyssop grow in Johnson County's climate?

Yes — Hyssop grows well in Johnson County's temperate climate. Johnson County averages a 193-day frost-free season, with last frost around April 13 and first frost around October 23.

🌱

Your Johnson County Garden Planner — Free

A 22-page printable planner built for Johnson County (Zone 6b). 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 Johnson County, MO. Local conditions may vary. Last updated: July 2026.

Sources & credits

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