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When to Plant Astilbe in Summit County, OH

Summit County, Ohio Zone 6b June

June to-do list for Summit County, Ohio

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

Avg. last frost May 4
Avg. first frost October 13
Soil temp (4") 66°F
Watering Moderate
Pest pressure High
Daylight 14.9 hrs
Coming up in July — start thinking about
  • Starting indoors: astilbe
  • First harvests: 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.

Summit County, Ohio is in USDA Zone 6b. The average last spring frost is May 4 and the first fall frost is October 13, giving you a growing season of approximately 162 days.

At an elevation of 1,309 feet, Summit County receives approximately 33.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Astilbe during the growing season.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Summit County, OH (Zone 6b) Moderate season
162 days
Last Spring Frost May 4
162 growing days
First Fall Frost October 13

Summit County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.7

Drainage

Well Drained

Astilbe Planting Risk Windows

Early Start (70% safe) ✓ Fits season (16 days to spare)
Start indoors: Feb 24 Transplant: May 5 🌸 Bloom: Jul 14 – Sep 22
Recommended (50%) ✓ Fits season (15 days to spare)
Start indoors: Mar 2 Transplant: May 11 🌸 Bloom: Jul 20 – Sep 28
Safe Start (90%) ✓ Fits season (10 days to spare)
Start indoors: Mar 20 Transplant: May 29 🌸 Bloom: Aug 7 – Oct 16

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 Summit County

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

Soil pH

Your soil pH (5.8–6.7) overlaps with Astilbe's range (6.0–8.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.0%) — Astilbe will thrive.

How to Plant Astilbe

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

Succession Planting Astilbe

2
successive plantings in your 162-day season

Sow every 8 weeks. Last sowing by Jul 05 to harvest before frost.

Astilbe Water Budget

Plant needs
1.5″/week
Rainfall provides
0.9″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,097 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 1.3" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 3.7" 0" ❄️ Dormant
May 6.5" 3.9" 2.6" 💧 Light watering
Jun 6.5" 3.6" 2.9" 💧 Light watering
Jul 6.5" 3.2" 3.3" 🚿 Regular watering
Aug 6.5" 3.9" 2.6" 💧 Light watering
Sep 6.5" 2.6" 3.9" 🚿 Regular watering
Oct 6.5" 2.9" 3.6" 🚿 Regular watering
Nov 2.4" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Summit 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 ~1,360 GDD — county provides 2,592 GDD Excellent fit

Astilbe Planting Timeline — Summit County, OH

Astilbe Planting Calendar

Activity When Date Range
Start Indoors March 2 Mar 2 – Mar 16
Transplant Outdoors May 11 May 11 – May 25
Bloom July 20 Jul 20 – Sep 28

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–8 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

162 days in Summit County

Growing Tips for Astilbe in Summit County

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

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 Summit County, OH?

Summit County is in Zone 6b with an average last frost of May 4. Plan your Astilbe planting based on this frost date — see the calendar above for exact timing.

What planting zone is Summit County, OH?

Summit County, Ohio is in USDA Hardiness Zone 6b. The average last spring frost is May 4 and first fall frost is October 13.

🌱

Your Summit County Garden Planner — Free

A 22-page printable planner built for Summit County (Zone 6b). 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 Summit County, OH. 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.