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When to plant Peonies in Fremont County, CO

In Fremont County, Peonies is a spring-only crop. Plant May 30–June 13 once soil hits 50°F.

When to Plant Peonies in Fremont County, CO

Fremont County, Colorado Zone 6a July

What to do in July

Your Fremont County, Colorado garden is entering a new phase. Here's what's on the schedule for July and why each task matters now.

Avg. last frost May 23
Avg. first frost September 25
Soil temp (4") 56°F
Watering High
Pest pressure High
Daylight 14.4 hrs
Looking ahead to August
  • First harvests: peonies

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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.

Fremont County, Colorado is in USDA Zone 6a. The average last spring frost is May 23 and the first fall frost is September 25, giving you a growing season of approximately 125 days.

At an elevation of 6,575 feet, Fremont County receives approximately 18.5 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Peonies to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Peonies successfully. Mulch heavily to conserve soil moisture.

Perennial Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting Fragrant
Fremont County, CO (Zone 6a) Short season
125 days
Last Spring Frost May 23
125 growing days
First Fall Frost September 25

Fremont County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.3

Drainage

Well Drained

Peonies Planting Risk Windows

Early Start (70% safe) ✓ Fits season (24 days to spare)
Transplant: May 18 🌸 Bloom: Jul 20 – Aug 24
Recommended (50%) ✓ Fits season (20 days to spare)
Transplant: May 30 🌸 Bloom: Aug 1 – Sep 5
Safe Start (90%) ✓ Fits season (15 days to spare)
Transplant: Jun 22 🌸 Bloom: Aug 24 – Sep 28

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 Fremont County

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

Soil pH

Your soil pH (6.7–8.3) is more alkaline than Peonies prefers (6.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.6%). 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
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 505 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 1.5" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 2.2" 0" ❄️ Dormant
May 4.3" 2" 2.3" 🚿 Regular watering
Jun 4.3" 1.5" 2.8" 🚿 Regular watering
Jul 4.3" 1.4" 2.9" 🚿 Regular watering
Aug 4.3" 1.7" 2.6" 🚿 Regular watering
Sep 4.3" 1.5" 2.8" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Fremont 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 ~1,365 GDD — county provides 1,625 GDD Good fit

Peonies Planting Timeline — Fremont County, CO

Peonies Planting Calendar

Activity When Date Range
Transplant Outdoors May 30 May 30 – Jun 13
Bloom August 1 Aug 1 – Sep 5

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

125 days in Fremont County

Growing Tips for Peonies in Fremont County

Direct sow Peonies outdoors after May 23 in Fremont County when soil has warmed and frost danger has passed.

Your 125.0-day growing season in Fremont County is tight for Peonies (90.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

Fremont County receives only 18" 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 Fremont County, CO?

Fremont County is in Zone 6a with an average last frost of May 23. Plan your Peonies planting based on this frost date — see the calendar above for exact timing.

What planting zone is Fremont County, CO?

Fremont County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is May 23 and first fall frost is September 25.

When should I plant Peonies in Fremont County, CO?

In Fremont County, CO, plant Peonies after the last frost (around May 23) and before the first frost (around September 25). Best results when soil holds above 50°F.

What growing zone is Fremont County, CO for Peonies?

Fremont County sits in USDA Zone 6a. Peonies grows reliably in zones 3a through 8b, so it's a good fit here.

Can Peonies grow in Fremont County's climate?

Yes — Peonies grows well in Fremont County's temperate climate. Fremont County averages a 125-day frost-free season, with last frost around May 23 and first frost around September 25.

🌱

Your Fremont County Garden Planner — Free

A 22-page printable planner built for Fremont County (Zone 6a). 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 Fremont County, CO. Local conditions may vary. Last updated: July 2026.

Sources & credits

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