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When to Plant Hyssop in Winona County, MN

Winona County, Minnesota Zone 4b May

What to do in May

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Winona County, Minnesota.

Avg. last frost April 30
Avg. first frost October 7
Soil temp (4") 54°F
Watering Low
Pest pressure Low
Daylight 14.6 hrs
  1. Transplant hyssop outside

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

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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.

Winona County, Minnesota is in USDA Zone 4b. The average last spring frost is April 30 and the first fall frost is October 7, giving you a growing season of approximately 160 days.

At an elevation of 1,396 feet, Winona County receives approximately 37.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Hyssop to ensure they mature before fall.

Winona County, MN (Zone 4b) Moderate season
160 days
Last Spring Frost April 30
160 growing days
First Fall Frost October 7

Winona County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (19 days to spare)
Transplant: May 2 🍅 Harvest: Jul 11 – Sep 12
Recommended (50%) ✓ Fits season (20 days to spare)
Transplant: May 7 🍅 Harvest: Jul 16 – Sep 17
Safe Start (90%) ✓ Fits season (14 days to spare)
Transplant: May 22 🍅 Harvest: Jul 31 – Oct 2

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 Winona County

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

Soil pH

Your soil pH (6.3–6.8) is within Hyssop's preferred range (6.0–8.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (5.2%) — Hyssop will thrive.

How to Plant Hyssop

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

Succession Planting Hyssop

2
successive plantings in your 160-day season

Sow every 8 weeks. Last sowing by Jul 09 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/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 1.7" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 2.2" 3.9" 0" ✅ Rainfall sufficient
May 2.2" 4.5" 0" ✅ Rainfall sufficient
Jun 2.2" 4.2" 0" ✅ Rainfall sufficient
Jul 2.2" 4.3" 0" ✅ Rainfall sufficient
Aug 2.2" 4.1" 0" ✅ Rainfall sufficient
Sep 2.2" 2.8" 0" ✅ Rainfall sufficient
Oct 2.2" 3.2" 0" ✅ Rainfall sufficient
Nov 2.6" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Winona 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 ~800 GDD — county provides 1,600 GDD Excellent fit

Hyssop Planting Timeline — Winona County, MN

Hyssop Planting Calendar

Activity When Date Range
Transplant Outdoors May 7 May 7 – May 21
Harvest July 16 Jul 16 – Sep 17

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July Harvest
August Harvest
September Harvest
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: ideal

🗺️ USDA Zone

Zone 4b

📆 Growing Season

160 days in Winona County

Growing Tips for Hyssop in Winona County

Direct sow Hyssop outdoors after April 30 in Winona 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 Winona County, MN?

Winona County is in Zone 4b with an average last frost of April 30. Plan your Hyssop planting based on this frost date — see the calendar above for exact timing.

What planting zone is Winona County, MN?

Winona County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is April 30 and first fall frost is October 7.

🌱

Your Winona County Garden Planner — Free

A 24-page printable planner built for Winona County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Winona County, MN. 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.