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When to plant Peonies in Keweenaw County, MI

Keweenaw County's 135-day season only supports one Peonies planting per year. Sow between June 2 and June 16 for the best chance at full maturity before October 1.

When to Plant Peonies in Keweenaw County, MI

Keweenaw County, Michigan Zone 5b June

Your June game plan for Keweenaw County, Michigan

We've pulled the most time-sensitive tasks for Keweenaw County, Michigan this June and put them front and centre. Tackle them in order.

Avg. last frost May 19
Avg. first frost October 1
Soil temp (4") 64°F
Watering Low
Pest pressure High
Daylight 15.7 hrs
  1. Time to transplant peonies

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

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Peonies (Paeonia lactiflora) are the crown jewels of the spring garden — magnificent, fragrant blooms in white, pink, and red that can last 100 years or more in the same spot with minimal care. Extremely cold-hardy and requiring a period of winter chill to bloom, they are most productive in Zones 3–7. Each established clump produces dozens of lush, fully double or semi-double flowers over a 2–3 week window in late spring. Virtually pest-free beyond the cosmetic presence of ants on buds (which are harmless). Once sited correctly, peonies rarely need dividing or moving.

Keweenaw County, Michigan is in USDA Zone 5b. The average last spring frost is May 19 and the first fall frost is October 1, giving you a growing season of approximately 135 days.

At an elevation of 1,035 feet, Keweenaw County receives approximately 40.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Peonies to ensure they mature before fall.

Perennial Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting Fragrant
Keweenaw County, MI (Zone 5b) Short season
135 days
Last Spring Frost May 19
135 growing days
First Fall Frost October 1

Keweenaw County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.9

Drainage

Well Drained

Peonies Planting Risk Windows

Early Start (70% safe) ✓ Fits season (9 days to spare)
Transplant: May 29 🌸 Bloom: Aug 7 – Sep 18
Recommended (50%) ✓ Fits season (9 days to spare)
Transplant: Jun 2 🌸 Bloom: Aug 11 – Sep 22
Safe Start (90%) ✓ Fits season (8 days to spare)
Transplant: Jun 18 🌸 Bloom: Aug 27 – Oct 8

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 Keweenaw County

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

Soil pH

Your soil pH (6.1–6.9) overlaps with Peonies's range (6.5–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.0%) — Peonies will thrive.

How to Plant Peonies

1.5"
Planting Depth
36"
Between Plants
48"
Between Rows

Peonies Water Budget

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

Monthly Watering Guide for Peonies

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

Month Peonies Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 3.7" 0" ❄️ Dormant
May 4.3" 4.2" 0.1" 💧 Light watering
Jun 4.3" 4.9" 0" ✅ Rainfall sufficient
Jul 4.3" 5" 0" ✅ Rainfall sufficient
Aug 4.3" 4.7" 0" ✅ Rainfall sufficient
Sep 4.3" 3.7" 0.6" 💧 Light watering
Oct 4.3" 3.2" 1.1" 💧 Light watering
Nov 2.9" 0" ❄️ Dormant
Dec 2.4" 0" ❄️ Dormant

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

Peonies 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.

Peonies needs ~1,129 GDD — county provides 1,451 GDD Good fit

Peonies Planting Timeline — Keweenaw County, MI

Peonies Planting Calendar

Activity When Date Range
Transplant Outdoors June 2 Jun 2 – Jun 16
Bloom August 11 Aug 11 – Sep 22

Plant 1.5" deep · 36" apart · Rows 48" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

135 days in Keweenaw County

Growing Tips for Peonies in Keweenaw County

Direct sow Peonies outdoors after May 19 in Keweenaw County when soil has warmed and frost danger has passed.

General growing tips

Plant bare-root divisions in fall (late September through October in Zones 3–7; November in Zone 8) with eyes facing upward and positioned exactly 1–2 inches below soil surface — deeper planting is the most common reason peonies fail to bloom. Choose a site with full sun and excellent drainage. Peonies require 6+ weeks of temperatures below 40°F (cold stratification period) for reliable bloom — they do not perform well in Zone 9+. Do not expect full bloom the first or second year; Year 3+ plants deliver the most impressive flowering. Avoid moving established plants. Stake double- flowered types before heavy blooms cause stems to flop. Cut stems to ground in fall after frost kills foliage to prevent botrytis overwinter.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Peonies in Keweenaw County, MI?

Keweenaw County is in Zone 5b with an average last frost of May 19. Plan your Peonies planting based on this frost date — see the calendar above for exact timing.

What planting zone is Keweenaw County, MI?

Keweenaw County, Michigan is in USDA Hardiness Zone 5b. The average last spring frost is May 19 and first fall frost is October 1.

When should I plant Peonies in Keweenaw County, MI?

In Keweenaw County, MI, plant Peonies after the last frost (around May 19) and before the first frost (around October 1). Best results when soil holds above 50°F.

What growing zone is Keweenaw County, MI for Peonies?

Keweenaw County sits in USDA Zone 5b. Peonies grows reliably in zones 3a through 8b, so it's a good fit here.

Can Peonies grow in Keweenaw County's climate?

Yes — Peonies grows well in Keweenaw County's temperate climate. Keweenaw County averages a 135-day frost-free season, with last frost around May 19 and first frost around October 1.

🌱

Your Keweenaw County Garden Planner — Free

A 22-page printable planner built for Keweenaw County (Zone 5b). 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 Keweenaw County, MI. Local conditions may vary. Last updated: June 2026.

Sources & credits

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