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When to Plant Serviceberries in Grand Isle County, VT

Grand Isle County, Vermont Zone 5a May

This month in Grand Isle County, Vermont

A quick May briefing for Grand Isle County, Vermont gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 6
Avg. first frost October 10
Soil temp (4") 55°F
Watering Moderate
Pest pressure Low
Daylight 14.6 hrs
  1. Time to transplant serviceberries

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

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

Grand Isle County, Vermont is in USDA Zone 5a. The average last spring frost is May 6 and the first fall frost is October 10, giving you a growing season of approximately 157 days.

At an elevation of 1,011 feet, Grand Isle County receives approximately 38.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Serviceberries to ensure they mature before fall.

Grand Isle County, VT (Zone 5a) Moderate season
157 days
Last Spring Frost May 6
157 growing days
First Fall Frost October 10
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Grand Isle County Soil Profile

Soil Type

Silt Loam

Soil pH

4.8-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 21
Recommended (50%) ✓ Fits season
Transplant: May 27
Safe Start (90%) ✓ Fits season
Transplant: Jun 7

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.

Soil Compatibility in Grand Isle County

How your county's soil matches Serviceberries's growing requirements.

Soil pH

Your soil pH (4.8–6.4) overlaps with Serviceberries's range (5.5–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Grand Isle County is excellent for Serviceberries — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.7%). Annual compost additions will help Serviceberries.

How to Plant Serviceberries

120"
Between Plants
144"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Serviceberries

Serviceberries needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Serviceberries Needs Rainfall You Supplement Action
Jan 2.5" 0" ❄️ Dormant
Feb 2.5" 0" ❄️ Dormant
Mar 3.2" 0" ❄️ Dormant
Apr 3.1" 0" ❄️ Dormant
May 4.3" 3.6" 0.7" 💧 Light watering
Jun 4.3" 3.5" 0.8" 💧 Light watering
Jul 4.3" 4.3" 0" ✅ Rainfall sufficient
Aug 4.3" 3.5" 0.8" 💧 Light watering
Sep 4.3" 3.6" 0.7" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 3.2" 0" ❄️ Dormant
Dec 2.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Grand Isle County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Serviceberries Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Serviceberries needs ~11,862 GDD — county provides 2,041 GDD May not mature

Serviceberries Planting Timeline — Grand Isle County, VT

Serviceberries Planting Calendar

Activity When Date Range
Transplant Outdoors May 27 May 27 – Jun 10

· 120" apart · Rows 144" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June Transplant Outdoors
July
August
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

730–1095 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

157 days in Grand Isle County

Growing Tips for Serviceberries in Grand Isle County

Direct sow Serviceberries outdoors after May 06 in Grand Isle County when soil has warmed and frost danger has passed.

Your 157.0-day growing season in Grand Isle County is tight for Serviceberries (730.0-1095.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Serviceberries in Grand Isle County, VT?

Grand Isle County is in Zone 5a with an average last frost of May 6. Plan your Serviceberries planting based on this frost date — see the calendar above for exact timing.

What planting zone is Grand Isle County, VT?

Grand Isle County, Vermont is in USDA Hardiness Zone 5a. The average last spring frost is May 6 and first fall frost is October 10.

🌱

Your Grand Isle County Garden Planner — Free

A 24-page printable planner built for Grand Isle County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Grand Isle County, VT. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.