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When to plant Hydrangeas in Moffat County County,

Moffat County County's short 99-day growing season means one Hydrangeas planting between June 21 and July 5. No fall crop in Zone 5b.

When to Plant Hydrangeas in Moffat County, CO

Moffat County, Colorado Zone 5b June

Your June planting checklist for Moffat County, Colorado

A quick June briefing for Moffat County, Colorado gardeners — what's urgent, what's next, and what can wait.

Avg. last frost June 7
Avg. first frost September 14
Soil temp (4") 49°F
Watering Critical
Pest pressure High
Daylight 14.9 hrs
  1. Plant out hydrangeas

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

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Hydrangeas (Hydrangea spp.) are among the most spectacular summer-blooming shrubs, with large mophead, lacecap, or panicle flower clusters lasting weeks in the garden and drying beautifully for arrangements. Native to Asia and North America alike, the genus spans several garden species with different hardiness and blooming habits. Panicle hydrangeas (H. paniculata, e.g., Limelight) are the most cold-hardy (Zone 3) and most reliable bloomers; smooth hydrangeas (H. arborescens, e.g., Annabelle) are equally tough. Bigleaf hydrangeas (H. macrophylla) are prized for blue/pink color-shifting blooms but require reliable snow cover or winter protection in Zones 5–6. Flower color in macrophylla types is determined by soil pH (acidic = blue, alkaline = pink).

Moffat County, Colorado is in USDA Zone 5b. The average last spring frost is June 7 and the first fall frost is September 14, giving you a growing season of approximately 99 days.

At an elevation of 6,597 feet, Moffat County receives approximately 12.3 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Hydrangeas during the growing season. With low rainfall, drip irrigation is essential for growing Hydrangeas successfully. Mulch heavily to conserve soil moisture.

Perennial Blooms in Summer Pollinator-friendly Good for cutting
Moffat County, CO (Zone 5b) Very short season
99 days
Last Spring Frost June 7
99 growing days
First Fall Frost September 14

Moffat County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.3

Drainage

Well Drained

Hydrangeas Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 19 Transplant: Jun 11 🌸 Bloom: Aug 27 – Nov 19
Recommended (50%) ✗ May not fit
Start indoors: Mar 29 Transplant: Jun 21 🌸 Bloom: Sep 6 – Nov 29
Safe Start (90%) ✗ May not fit
Start indoors: Apr 11 Transplant: Jul 4 🌸 Bloom: Sep 19 – Dec 12

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 Moffat County

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

Soil pH

Your soil pH (6.8–8.3) is more alkaline than Hydrangeas prefers (5.5–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Hydrangeas.

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Hydrangeas.

How to Plant Hydrangeas

1"
Planting Depth
48"
Between Plants
60"
Between Rows

Hydrangeas Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 823 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Hydrangeas

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

Month Hydrangeas Needs Rainfall You Supplement Action
Jan 1" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.1" 0" ❄️ Dormant
Apr 1.2" 0" ❄️ Dormant
May 1.4" 0" ❄️ Dormant
Jun 4.3" 0.8" 3.5" 🚿 Regular watering
Jul 4.3" 1" 3.3" 🚿 Regular watering
Aug 4.3" 1.4" 2.9" 🚿 Regular watering
Sep 4.3" 1.1" 3.2" 🚿 Regular watering
Oct 1" 0" ❄️ Dormant
Nov 0.8" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

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

Hydrangeas 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.

Hydrangeas needs ~1,740 GDD — county provides 1,435 GDD May not mature

Hydrangeas Planting Timeline — Moffat County, CO

Hydrangeas Planting Calendar

Activity When Date Range
Start Indoors March 29 Mar 29 – Apr 12
Transplant Outdoors June 21 Jun 21 – Jul 5
Bloom September 6 Sep 6 – Nov 29

Plant 1" deep · 48" apart · Rows 60" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

90–150 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

99 days in Moffat County

Growing Tips for Hydrangeas in Moffat County

Direct sow Hydrangeas outdoors after June 07 in Moffat County when soil has warmed and frost danger has passed.

Your 99.0-day growing season in Moffat County is tight for Hydrangeas (90.0-150.0 days to maturity). Start indoors and choose early-maturing varieties.

Moffat County receives only 12" of rain annually. Hydrangeas needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant container-grown specimens in spring or fall, spacing at least 3–5 feet apart to allow for mature shrub spread. Most hydrangeas prefer morning sun with afternoon shade, especially in Zones 7+. Keep consistently moist — the name derives from the Greek for water vessel. Prune panicle and smooth types in late winter/early spring (they bloom on new wood). Prune bigleaf types only lightly after bloom; cutting stems in fall removes next year's buds. In Zone 5–6, protect bigleaf varieties with burlap or wire cages filled with leaves over winter. Fall planting (Zones 5+) gives excellent root establishment before summer heat. Year 2+ plants reach full size and bloom.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Hydrangeas in Moffat County, CO?

Moffat County is in Zone 5b with an average last frost of June 7. Plan your Hydrangeas planting based on this frost date — see the calendar above for exact timing.

What planting zone is Moffat County, CO?

Moffat County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is June 7 and first fall frost is September 14.

When should I plant Hydrangeas in Moffat County County, ?

In Moffat County County, , plant Hydrangeas after the last frost (around June 7) and before the first frost (around September 14). Best results when soil holds above 50°F.

What growing zone is Moffat County County, for Hydrangeas?

Moffat County County sits in USDA Zone 5b. Hydrangeas grows reliably in zones 3a through 9a, so it's a good fit here.

Can Hydrangeas grow in Moffat County County's climate?

Yes — Hydrangeas grows well in Moffat County County's temperate climate. Moffat County County averages a 99-day frost-free season, with last frost around June 7 and first frost around September 14.

🌱

Your Moffat County Garden Planner — Free

A 22-page printable planner built for Moffat 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 Moffat 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.