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When to Plant Astilbe in Schuylkill County, PA

Schuylkill County, Pennsylvania Zone 6b June

June in the garden — Schuylkill County, Pennsylvania

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Schuylkill County, Pennsylvania.

Avg. last frost April 17
Avg. first frost October 27
Soil temp (4") 72°F
Watering Moderate
Pest pressure High
Daylight 14.9 hrs
  1. Sow astilbe in trays indoors

    Label every cell. You will absolutely forget which is which otherwise.

Get ahead of July
  • 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.

Schuylkill County, Pennsylvania is in USDA Zone 6b. The average last spring frost is April 17 and the first fall frost is October 27, giving you a growing season of approximately 193 days.

At an elevation of 253 feet, Schuylkill County receives approximately 43.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Astilbe during the growing season.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Schuylkill County, PA (Zone 6b) Moderate season
193 days
Last Spring Frost April 17
193 growing days
First Fall Frost October 27

Schuylkill County Soil Profile

Soil Type

Silt Loam

Soil pH

4.8-6.8

Drainage

Well Drained

Astilbe Planting Risk Windows

Early Start (70% safe) ✓ Fits season (47 days to spare)
Start indoors: Feb 5 Transplant: Apr 16 🌸 Bloom: Jun 25 – Sep 3
Recommended (50%) ✓ Fits season (46 days to spare)
Start indoors: Feb 13 Transplant: Apr 24 🌸 Bloom: Jul 3 – Sep 11
Safe Start (90%) ✓ Fits season (39 days to spare)
Start indoors: Mar 5 Transplant: May 14 🌸 Bloom: Jul 23 – Oct 1

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 Schuylkill County

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

Soil pH

Your soil pH (4.8–6.8) is more acidic than Astilbe prefers (6.0–8.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.0%). Annual compost additions will help Astilbe.

How to Plant Astilbe

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

Succession Planting Astilbe

3
successive plantings in your 193-day season

Sow every 8 weeks. Last sowing by Jul 19 to harvest before frost.

Astilbe Water Budget

Plant needs
1.5″/week
Rainfall provides
0.9″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 958 gal / 100 sq ft

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 2.7" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 4" 0" ❄️ Dormant
Apr 6.5" 3.8" 2.7" 💧 Light watering
May 6.5" 4.3" 2.2" 💧 Light watering
Jun 6.5" 3.6" 2.9" 💧 Light watering
Jul 6.5" 3.9" 2.6" 💧 Light watering
Aug 6.5" 4.4" 2.1" 💧 Light watering
Sep 6.5" 3.8" 2.7" 💧 Light watering
Oct 6.5" 3.9" 2.6" 💧 Light watering
Nov 3" 0" ❄️ Dormant
Dec 3.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Schuylkill 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 ~1,551 GDD — county provides 3,522 GDD Excellent fit

Astilbe Planting Timeline — Schuylkill County, PA

Astilbe Planting Calendar

Activity When Date Range
Start Indoors February 13 Feb 13 – Feb 27
Transplant Outdoors April 24 Apr 24 – May 8
Bloom July 3 Jul 3 – Sep 11

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March
April Transplant Outdoors
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 · 1-2 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–8 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

193 days in Schuylkill County

Growing Tips for Astilbe in Schuylkill County

Direct sow Astilbe outdoors after April 17 in Schuylkill 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 Schuylkill County, PA?

Schuylkill County is in Zone 6b with an average last frost of April 17. Plan your Astilbe planting based on this frost date — see the calendar above for exact timing.

What planting zone is Schuylkill County, PA?

Schuylkill County, Pennsylvania is in USDA Hardiness Zone 6b. The average last spring frost is April 17 and first fall frost is October 27.

🌱

Your Schuylkill County Garden Planner — Free

A 22-page printable planner built for Schuylkill 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 Schuylkill County, PA. 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.