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When to plant Astilbe in Sumner County County,

Sumner County County's short 198-day growing season means one Astilbe planting between April 18 and May 2. No fall crop in Zone 7a.

When to Plant Astilbe in Sumner County, KS

Sumner County, Kansas Zone 7a June

Your June game plan for Sumner County, Kansas

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

Avg. last frost April 11
Avg. first frost October 26
Soil temp (4") 72°F
Watering Low
Pest pressure High
Daylight 14.5 hrs
  1. Get astilbe seeds going inside

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

  2. Basket week: astilbe

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

A few tasks this June that'll pay off in 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.

Sumner County, Kansas is in USDA Zone 7a. The average last spring frost is April 11 and the first fall frost is October 26, giving you a growing season of approximately 198 days.

At an elevation of 637 feet, Sumner County receives approximately 29 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Astilbe during the growing season.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Sumner County, KS (Zone 7a) Moderate season
198 days
Last Spring Frost April 11
198 growing days
First Fall Frost October 26

Sumner County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.8

Drainage

Well Drained

Astilbe Planting Risk Windows

Early Start (70% safe) ✓ Fits season (66 days to spare)
Start indoors: Feb 1 Transplant: Apr 12 🌸 Bloom: Jun 21 – Aug 16
Recommended (50%) ✓ Fits season (65 days to spare)
Start indoors: Feb 7 Transplant: Apr 18 🌸 Bloom: Jun 27 – Aug 22
Safe Start (90%) ✓ Fits season (68 days to spare)
Start indoors: Feb 21 Transplant: May 2 🌸 Bloom: Jul 11 – Sep 5

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 Sumner County

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

Soil pH

Your soil pH (6.4–7.8) is within Astilbe's preferred range (6.0–8.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.6%). 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 198-day season

Sow every 8 weeks. Last sowing by Jul 18 to harvest before frost.

Astilbe Water Budget

Plant needs
1.5″/week
Rainfall provides
0.6″/week
You supply
1.1″/week
Watering frequency 2-3 times/week
Season total 1,871 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 0.7" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 6.5" 3" 3.5" 🚿 Regular watering
May 6.5" 4.4" 2.1" 💧 Light watering
Jun 6.5" 4.2" 2.3" 💧 Light watering
Jul 6.5" 3.4" 3.1" 💧 Light watering
Aug 6.5" 4" 2.5" 💧 Light watering
Sep 6.5" 3" 3.5" 🚿 Regular watering
Oct 6.5" 1.7" 4.8" 🚿 Regular watering
Nov 1.1" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Sumner 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 ~1,169 GDD — county provides 2,722 GDD Excellent fit

Astilbe Planting Timeline — Sumner County, KS

Astilbe Planting Calendar

Activity When Date Range
Start Indoors February 7 Feb 7 – Feb 21
Transplant Outdoors April 18 Apr 18 – May 2
Bloom June 27 Jun 27 – Aug 22

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 Bloom
July Bloom
August Bloom
September
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: ideal

🗺️ USDA Zone

Zone 7a

📆 Growing Season

198 days in Sumner County

Growing Tips for Astilbe in Sumner County

Direct sow Astilbe outdoors after April 11 in Sumner 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 Sumner County, KS?

Sumner County is in Zone 7a with an average last frost of April 11. Plan your Astilbe planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sumner County, KS?

Sumner County, Kansas is in USDA Hardiness Zone 7a. The average last spring frost is April 11 and first fall frost is October 26.

When should I plant Astilbe in Sumner County County, ?

In Sumner County County, , plant Astilbe after the last frost (around April 11) and before the first frost (around October 26). Best results when soil holds above 50°F.

What growing zone is Sumner County County, for Astilbe?

Sumner County County sits in USDA Zone 7a. Astilbe grows reliably in zones 3a through 8b, so it's a good fit here.

Can Astilbe grow in Sumner County County's climate?

Yes — Astilbe grows well in Sumner County County's temperate climate. Sumner County County averages a 198-day frost-free season, with last frost around April 11 and first frost around October 26.

🌱

Your Sumner County Garden Planner — Free

A 22-page printable planner built for Sumner County (Zone 7a). 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 Sumner County, KS. 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.