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When to Plant Hyssop in USDA Zone 4a

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.

In Zone 4a, the average last spring frost is around May 6 and the first fall frost is around September 28, giving you a growing season of approximately 145 days.

Zone 4a Short season
145 days
Last Spring Frost May 6
145 growing days
First Fall Frost September 28

Hyssop Planting Timeline — Zone 4a

Where Is USDA Zone 4a?

The map below highlights the states that contain Zone 4a. Click any state to see the Hyssop planting schedule for that location.

Prints a clean, ink-friendly version without maps or navigation.

Hyssop Planting Calendar — Zone 4a

Activity When Date Range
Transplant Outdoors May 13 May 13 – May 27
Harvest July 22 Jul 22 – Sep 23

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

Free Zone 4a Planting Calendar PDF

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Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low — drought tolerant

Days to Maturity

70–90 days

Soil pH

6 – 8

Zone Temperature Range

-30°F to -25°F average annual minimum

Growing Season

145 days (Zone 4a average)

Planting Specifications

Planting Depth0.5 inches
Plant Spacing8 inches apart
Row Spacing12 inches between rows

Growing Tips for Zone 4a

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

Level Up Your Garden

Saving Hyssop Seeds

Recommended for Your Garden

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Seedling Heat Mat $15-35

Warm soil for faster germination of heat-loving crops like tomatoes and peppers.

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Floating Row Covers $12-30

Protect plants from frost, wind, and pests while letting light and water through.

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Frequently Asked Questions

When should I plant Hyssop in Zone 4a?

In Zone 4a, plan your Hyssop planting around the average last frost date of May 6. Transplant seedlings around May 13.

Can Hyssop grow in Zone 4a?

Yes, Hyssop can grow well in Zone 4a, hardy in USDA zones 3a through 9b. Zone 4a has a growing season of approximately 145 days, which is sufficient for Hyssop (70-90 days to maturity).

When can I harvest Hyssop in Zone 4a?

In Zone 4a, expect to harvest Hyssop from July 22 – September 23. Hyssop takes 70-90 days from planting to harvest.

What is the last frost date for Zone 4a?

The average last spring frost in Zone 4a is around May 6, and the first fall frost is around September 28. This gives a growing season of approximately 145 days. These are 50% probability dates — actual frost dates vary year to year.

What should I plant next to Hyssop?

Good companion plants for Hyssop include Cabbage, Grapes, Lavender. These companions can help with pest control, pollination, and nutrient sharing.

🌱

Plan Your Garden with Confidence

Get our free Garden Planner — organize your planting dates for Zone 4a, track your crops, and plan your garden season from seed to harvest.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals, University Cooperative Extension planting guides. Planting dates are estimates based on average frost dates — local conditions may vary. Last updated: April 2026.