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When to Plant Astilbe in Uinta County, WY

Uinta County, Wyoming Zone 5a June

What to do in June

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

Avg. last frost June 17
Avg. first frost August 31
Soil temp (4") 50°F
Watering High
Pest pressure High
Daylight 15 hrs
To set up a strong July, finish these tasks
  • Transplants going out: astilbe

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Astilbe (Astilbe x arendsii) is a premier perennial for shaded, moist gardens, producing feathery plume-like flower spikes in shades of pink, red, white, and lavender above deeply cut, ferny foliage. Originating in Asia and naturalized in shade gardens worldwide, astilbe thrives where many sun-lovers fail: under trees, beside water features, or in persistently moist woodland borders. The dried flower plumes remain attractive through fall and winter. Different cultivars extend the bloom season from early summer through early fall when several varieties are combined.

Uinta County, Wyoming is in USDA Zone 5a. The average last spring frost is June 17 and the first fall frost is August 31, giving you a growing season of approximately 75 days.

At an elevation of 5,768 feet, Uinta County receives approximately 23.5 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Astilbe to ensure they mature before fall.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Uinta County, WY (Zone 5a) Very short season
75 days
Last Spring Frost June 17
75 growing days
First Fall Frost August 31
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Uinta County Soil Profile

Soil Type

Loam

Soil pH

6.3-8.3

Drainage

Well Drained

Astilbe Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 8 Transplant: Jun 24 🌸 Bloom: Sep 9 – Nov 11
Recommended (50%) ✗ May not fit
Start indoors: Apr 15 Transplant: Jul 1 🌸 Bloom: Sep 16 – Nov 18
Safe Start (90%) ✗ May not fit
Start indoors: Apr 22 Transplant: Jul 8 🌸 Bloom: Sep 23 – Nov 25

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 Uinta County

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

Soil pH

Your soil pH (6.3–8.3) overlaps with Astilbe's range (6.0–8.0), though not a perfect match.

Soil Texture

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

Organic Matter

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

How to Plant Astilbe

1.5"
Planting Depth
18"
Between Plants
24"
Between Rows

Astilbe Water Budget

Plant needs
1.5″/week
Rainfall provides
1.3″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 147 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Astilbe

Astilbe needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Astilbe Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.8" 0" ❄️ Dormant
May 2.7" 0" ❄️ Dormant
Jun 6.5" 1.8" 4.7" 🚿 Regular watering
Jul 6.5" 1.8" 4.7" 🚿 Regular watering
Aug 6.5" 2.2" 4.3" 🚿 Regular watering
Sep 2.2" 0" ❄️ Dormant
Oct 1.9" 0" ❄️ Dormant
Nov 1.7" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

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

Astilbe 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.

Astilbe needs ~978 GDD — county provides 862 GDD May not mature

Astilbe Planting Timeline — Uinta County, WY

Astilbe Planting Calendar

Activity When Date Range
Start Indoors April 15 Apr 15 – Apr 29
Transplant Outdoors July 1 Jul 1 – Jul 15
Bloom September 16 Sep 16 – Nov 18

Plant 1.5" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · Only during dry spells

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–8 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

75 days in Uinta County

Growing Tips for Astilbe in Uinta County

Direct sow Astilbe outdoors after June 17 in Uinta County when soil has warmed and frost danger has passed.

Your 75.0-day growing season in Uinta County is tight for Astilbe (70.0-100.0 days to maturity). Start indoors and choose early-maturing varieties.

Uinta County receives only 24" of rain annually. Astilbe needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant bare-root crowns in spring as soon as the ground is workable, setting eyes 1–2 inches below soil level. Fall planting (Zones 4+) is equally effective. Consistent moisture is non-negotiable — astilbe will wilt and scorch in drought. Amend with generous compost to improve moisture retention. Partial shade (morning sun, afternoon shade) is ideal; deep shade reduces bloom but foliage remains. Fertilize lightly in spring with a balanced slow-release granular. Divide every 3–5 years in early spring as clumps become congested. Leave plumes standing through winter for ornamental interest and wildlife value. Year 2+ plants produce the fullest bloom spikes; first-year crowns may flower lightly or not at all.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Astilbe in Uinta County, WY?

Uinta County is in Zone 5a with an average last frost of June 17. Plan your Astilbe planting based on this frost date — see the calendar above for exact timing.

What planting zone is Uinta County, WY?

Uinta County, Wyoming is in USDA Hardiness Zone 5a. The average last spring frost is June 17 and first fall frost is August 31.

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Your Uinta County Garden Planner — Free

A 22-page printable planner built for Uinta County (Zone 5a). 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 Uinta County, WY. 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.