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When to Plant Hyssop in Custer 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.

Custer County, Oklahoma is in USDA Zone 7a. The average last spring frost is April 8 and the first fall frost is October 31, giving you a growing season of approximately 206 days.

At an elevation of 767 feet, Custer County receives approximately 31.6 inches of rainfall annually with predominantly loam soil. Summer highs average 89ยฐF, providing good warmth for Hyssop during the growing season.

Custer County, OK (Zone 7a) Long season
206 days
Last Spring Frost April 8
206 growing days
First Fall Frost October 31

Custer County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (64 days to spare)
Transplant: Apr 10 🍅 Harvest: Jun 19 – Aug 21
Recommended (50%) ✓ Fits season (66 days to spare)
Transplant: Apr 15 🍅 Harvest: Jun 24 – Aug 26
Safe Start (90%) ✓ Fits season (72 days to spare)
Transplant: Apr 25 🍅 Harvest: Jul 4 – Sep 5

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
0.6″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Hyssop needs ~1,340 GDD — county provides 3,450 GDD Excellent fit

Hyssop Planting Timeline โ€” Custer County, OK

Hyssop Planting Calendar

Activity When Date Range
Transplant Outdoors April 15 Apr 15 โ€“ Apr 29
Harvest June 24 Jun 24 โ€“ Aug 26

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

206 days

Growing Tips for Custer 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 Custer County, OK?

Custer County is in Zone 7a with an average last frost of April 8. Plan your Hyssop planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Custer County, OK?

Custer County, Oklahoma is in USDA Hardiness Zone 7a. The average last spring frost is April 8 and first fall frost is October 31.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Custer 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 Custer County, OK. Local conditions may vary. Last updated: April 2026.