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When to Plant Hyssop in Seminole County, OK

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.

Seminole County, Oklahoma is in USDA Zone 7a. The average last spring frost is March 31 and the first fall frost is November 6, giving you a growing season of approximately 220 days.

At an elevation of 961 feet, Seminole County receives approximately 20.7 inches of rainfall annually with predominantly loam soil. Summer highs average 94ยฐF, providing good warmth for Hyssop during the growing season.

Seminole County, OK (Zone 7a) Long season
220 days
Last Spring Frost March 31
220 growing days
First Fall Frost November 6

Seminole County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (78 days to spare)
Transplant: Mar 31 🍅 Harvest: Jun 9 – Aug 11
Recommended (50%) ✓ Fits season (80 days to spare)
Transplant: Apr 7 🍅 Harvest: Jun 16 – Aug 18
Safe Start (90%) ✓ Fits season (82 days to spare)
Transplant: Apr 22 🍅 Harvest: Jul 1 – Sep 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.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.4″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 246 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Hyssop needs ~1,640 GDD — county provides 4,510 GDD Excellent fit

Hyssop Planting Timeline โ€” Seminole County, OK

Hyssop Planting Calendar

Activity When Date Range
Transplant Outdoors April 7 Apr 7 โ€“ Apr 21
Harvest June 16 Jun 16 โ€“ Aug 18

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Transplant Outdoors
May โ€”
June Harvest
July Harvest
August Harvest
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

70โ€“90 days

Soil pH

6 โ€“ 8

USDA Zone

Zone 7a

Growing Season

220 days

Growing Tips for Seminole County

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

Frequently Asked Questions

When should I plant Hyssop in Seminole County, OK?

Seminole County is in Zone 7a with an average last frost of March 31. Plan your Hyssop planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Seminole County, OK?

Seminole County, Oklahoma is in USDA Hardiness Zone 7a. The average last spring frost is March 31 and first fall frost is November 6.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Seminole County gardeners in Zone 7a organize planting dates, track what's growing, and never miss a planting window.

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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 Seminole County, OK. Local conditions may vary. Last updated: April 2026.