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When to plant Peonies in Jackson County County,

In Jackson County County, Peonies is a spring-only crop. Plant June 27–July 11 once soil hits 50°F.

When to Plant Peonies in Jackson County, CO

Jackson County, Colorado Zone 4b June

Jackson County, Colorado gardeners: here's your June plan

If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.

Avg. last frost June 13
Avg. first frost September 4
Soil temp (4") 49°F
Watering High
Pest pressure Moderate
Daylight 14.9 hrs
  1. Time to transplant peonies

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

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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.

Jackson County, Colorado is in USDA Zone 4b. The average last spring frost is June 13 and the first fall frost is September 4, giving you a growing season of approximately 83 days.

At an elevation of 5,388 feet, Jackson County receives approximately 20.9 inches of rainfall annually with predominantly loam soil. Summer highs average 80°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
Jackson County, CO (Zone 4b) Very short season
83 days
Last Spring Frost June 13
83 growing days
First Fall Frost September 4
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Jackson County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.1

Drainage

Well Drained

Peonies Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Jun 22 🌸 Bloom: Aug 31 – Oct 5
Recommended (50%) ✗ May not fit
Transplant: Jun 27 🌸 Bloom: Sep 5 – Oct 10
Safe Start (90%) ✗ May not fit
Transplant: Jul 9 🌸 Bloom: Sep 17 – Oct 22

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 Jackson County

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

Soil pH

Your soil pH (6.6–8.1) is more alkaline than Peonies prefers (6.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Peonies.

How to Plant Peonies

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

Peonies Water Budget

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

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.6" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.3" 0" ❄️ Dormant
May 2.2" 0" ❄️ Dormant
Jun 4.3" 1.7" 2.6" 🚿 Regular watering
Jul 4.3" 1.7" 2.6" 🚿 Regular watering
Aug 4.3" 2.5" 1.8" 💧 Light watering
Sep 4.3" 1.5" 2.8" 🚿 Regular watering
Oct 2.1" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Jackson 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 ~1,050 GDD — county provides 830 GDD May not mature

Peonies Planting Timeline — Jackson County, CO

Peonies Planting Calendar

Activity When Date Range
Transplant Outdoors June 27 Jun 27 – Jul 11
Bloom September 5 Sep 5 – Oct 10

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 4b

📆 Growing Season

83 days in Jackson County

Growing Tips for Peonies in Jackson County

Direct sow Peonies outdoors after June 13 in Jackson County when soil has warmed and frost danger has passed.

Your 83.0-day growing season in Jackson County is tight for Peonies (90.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

Jackson County receives only 21" of rain annually. Peonies needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Jackson County, CO?

Jackson County is in Zone 4b with an average last frost of June 13. Plan your Peonies planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jackson County, CO?

Jackson County, Colorado is in USDA Hardiness Zone 4b. The average last spring frost is June 13 and first fall frost is September 4.

When should I plant Peonies in Jackson County County, ?

In Jackson County County, , plant Peonies after the last frost (around June 13) and before the first frost (around September 4). Best results when soil holds above 50°F.

What growing zone is Jackson County County, for Peonies?

Jackson County County sits in USDA Zone 4b. Peonies grows reliably in zones 3a through 8b, so it's a good fit here.

Can Peonies grow in Jackson County County's climate?

Yes — Peonies grows well in Jackson County County's temperate climate. Jackson County County averages a 83-day frost-free season, with last frost around June 13 and first frost around September 4.

🌱

Your Jackson County Garden Planner — Free

A 22-page printable planner built for Jackson County (Zone 4b). 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 Jackson County, CO. 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.