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When to plant Peonies in Phillips County County,

Plant Peonies in Phillips County County during the brief May 18–June 1 window. With 156 frost-free days, fall plantings can't mature before October 7.

When to Plant Peonies in Phillips County, CO

Phillips County, Colorado Zone 5b June

This month in Phillips County, Colorado

Here's what deserves your attention in Phillips County, Colorado this month. Everything below is tailored to Zone 5b and timed around your local frost dates.

Avg. last frost May 4
Avg. first frost October 7
Soil temp (4") 54°F
Watering High
Pest pressure High
Daylight 14.9 hrs
A few tasks this June that'll pay off in July
  • 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.

Phillips County, Colorado is in USDA Zone 5b. The average last spring frost is May 4 and the first fall frost is October 7, giving you a growing season of approximately 156 days.

At an elevation of 5,494 feet, Phillips County receives approximately 21.1 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Peonies during the growing season.

Perennial Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting Fragrant
Phillips County, CO (Zone 5b) Moderate season
156 days
Last Spring Frost May 4
156 growing days
First Fall Frost October 7

Phillips County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.8

Drainage

Well Drained

Peonies Planting Risk Windows

Early Start (70% safe) ✓ Fits season (31 days to spare)
Transplant: May 14 🌸 Bloom: Jul 23 – Sep 3
Recommended (50%) ✓ Fits season (30 days to spare)
Transplant: May 18 🌸 Bloom: Jul 27 – Sep 7
Safe Start (90%) ✓ Fits season (25 days to spare)
Transplant: Jun 2 🌸 Bloom: Aug 11 – Sep 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 Phillips County

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

Soil pH

Your soil pH (6.5–7.8) is more alkaline than Peonies prefers (6.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Peonies.

Organic Matter

Organic matter is moderate (2.4%). 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
0.9″/week
Watering frequency 2-3 times/week
Season total 1,219 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 1.3" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 1.9" 0" ❄️ Dormant
May 4.3" 2.8" 1.5" 💧 Light watering
Jun 4.3" 1.5" 2.8" 🚿 Regular watering
Jul 4.3" 1.6" 2.7" 🚿 Regular watering
Aug 4.3" 2.5" 1.8" 💧 Light watering
Sep 4.3" 1.7" 2.6" 🚿 Regular watering
Oct 4.3" 1.8" 2.5" 🚿 Regular watering
Nov 1.7" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Phillips 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 ~1,601 GDD — county provides 2,379 GDD Excellent fit

Peonies Planting Timeline — Phillips County, CO

Peonies Planting Calendar

Activity When Date Range
Transplant Outdoors May 18 May 18 – Jun 1
Bloom July 27 Jul 27 – Sep 7

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 Bloom
August Bloom
September Bloom
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

156 days in Phillips County

Growing Tips for Peonies in Phillips County

Direct sow Peonies outdoors after May 04 in Phillips County when soil has warmed and frost danger has passed.

Phillips 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 Phillips County, CO?

Phillips County is in Zone 5b with an average last frost of May 4. Plan your Peonies planting based on this frost date — see the calendar above for exact timing.

What planting zone is Phillips County, CO?

Phillips County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 4 and first fall frost is October 7.

When should I plant Peonies in Phillips County County, ?

In Phillips County County, , plant Peonies after the last frost (around May 4) and before the first frost (around October 7). Best results when soil holds above 50°F.

What growing zone is Phillips County County, for Peonies?

Phillips County 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 Phillips County County's climate?

Yes — Peonies grows well in Phillips County County's temperate climate. Phillips County County averages a 156-day frost-free season, with last frost around May 4 and first frost around October 7.

🌱

Your Phillips County Garden Planner — Free

A 22-page printable planner built for Phillips 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 Phillips 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.