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When to Plant Persimmon in Sweet Grass County, MT

Persimmons are ornamental trees producing sweet, honey-flavored fruits in fall. American persimmons are astringent until fully ripe while Asian types can be eaten firm.

Sweet Grass County, Montana is in USDA Zone 4b. The average last spring frost is May 22 and the first fall frost is September 19, giving you a growing season of approximately 120 days.

At an elevation of 7,534 feet, Sweet Grass County receives approximately 16.9 inches of rainfall annually with predominantly loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Persimmon to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Persimmon successfully. Mulch heavily to conserve soil moisture.

Sweet Grass County, MT (Zone 4b) Short season
120 days
Last Spring Frost May 22
120 growing days
First Fall Frost September 19

Sweet Grass County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: Jun 13
Recommended (50%) ✓ Fits season
Transplant: Jun 19
Safe Start (90%) ✓ Fits season
Transplant: Jul 4

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
1.0″/week
Rainfall provides
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 524 gal / 100 sq ft
Drought risk

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

Persimmon needs ~20,988 GDD — county provides 1,380 GDD May not mature

Persimmon Planting Timeline โ€” Sweet Grass County, MT

Persimmon Planting Calendar

Activity When Date Range
Transplant Outdoors June 19 Jun 19 โ€“ Jul 3

ยท 120" apart ยท Rows 144" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

1095โ€“2555 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 4b

Growing Season

120 days

Growing Tips for Sweet Grass County

Choose self-fertile varieties or plant male and female trees. American types must be fully soft-ripe before eating. Asian varieties may be eaten when firm. Minimal pruning needed.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Persimmon in Sweet Grass County, MT?

Sweet Grass County is in Zone 4b with an average last frost of May 22. Plan your Persimmon planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Sweet Grass County, MT?

Sweet Grass County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 22 and first fall frost is September 19.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Sweet Grass County gardeners in Zone 4b 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 Sweet Grass County, MT. Local conditions may vary. Last updated: April 2026.