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When to Plant Serviceberries in Knox County, ME

Serviceberries (saskatoons) are attractive native shrubs or small trees producing sweet, blueberry-like fruits. They have beautiful spring flowers and vibrant fall color.

Knox County, Maine is in USDA Zone 5b. The average last spring frost is May 2 and the first fall frost is October 12, giving you a growing season of approximately 163 days.

At an elevation of 408 feet, Knox County receives approximately 41.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Serviceberries to ensure they mature before fall.

Knox County, ME (Zone 5b) Moderate season
163 days
Last Spring Frost May 2
163 growing days
First Fall Frost October 12

Knox County Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 18
Recommended (50%) ✓ Fits season
Transplant: May 23
Safe Start (90%) ✓ Fits season
Transplant: Jun 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
1.0″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Serviceberries needs ~11,178 GDD — county provides 1,996 GDD May not mature

Serviceberries Planting Timeline โ€” Knox County, ME

Serviceberries Planting Calendar

Activity When Date Range
Transplant Outdoors May 23 May 23 โ€“ Jun 6

ยท 120" apart ยท Rows 144" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May Transplant Outdoors
June Transplant Outdoors
July โ€”
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

730โ€“1095 days

Soil pH

5.5 โ€“ 7

USDA Zone

Zone 5b

Growing Season

163 days

Growing Tips for Knox County

Plant in well-drained soil. Minimal pruning needed beyond removing dead wood. Protect fruit from birds with netting. Berries ripen in early summer and are excellent fresh or in pies.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Serviceberries in Knox County, ME?

Knox County is in Zone 5b with an average last frost of May 2. Plan your Serviceberries planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Knox County, ME?

Knox County, Maine is in USDA Hardiness Zone 5b. The average last spring frost is May 2 and first fall frost is October 12.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Knox County gardeners in Zone 5b 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 Knox County, ME. Local conditions may vary. Last updated: April 2026.