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When to plant Astilbe in Harvey County, KS

Harvey County sits in cold Zone 6b. Plant Astilbe April 22–May 6 for the single annual harvest; the October 24 first frost closes the window.

When to Plant Astilbe in Harvey County, KS

Harvey County, Kansas Zone 6b June

June to-do list for Harvey County, Kansas

Here's what deserves your attention in Harvey County, Kansas this month. Everything below is tailored to Zone 6b and timed around your local frost dates.

Avg. last frost April 15
Avg. first frost October 24
Soil temp (4") 75°F
Watering Low
Pest pressure High
Daylight 14.6 hrs
  1. Start astilbe under lights

    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.

Harvey County, Kansas is in USDA Zone 6b. The average last spring frost is April 15 and the first fall frost is October 24, giving you a growing season of approximately 192 days.

At an elevation of 872 feet, Harvey County receives approximately 23.2 inches of rainfall annually with predominantly 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
Harvey County, KS (Zone 6b) Moderate season
192 days
Last Spring Frost April 15
192 growing days
First Fall Frost October 24

Harvey County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.1

Drainage

Well Drained

Astilbe Planting Risk Windows

Early Start (70% safe) ✓ Fits season (43 days to spare)
Start indoors: Feb 5 Transplant: Apr 16 🌸 Bloom: Jun 25 – Sep 3
Recommended (50%) ✓ Fits season (45 days to spare)
Start indoors: Feb 11 Transplant: Apr 22 🌸 Bloom: Jul 1 – Sep 9
Safe Start (90%) ✓ Fits season (44 days to spare)
Start indoors: Feb 23 Transplant: May 4 🌸 Bloom: Jul 13 – Sep 21

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 Harvey County

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

Soil pH

Your soil pH (6.5–7.1) is within Astilbe's preferred range (6.0–8.0).

Soil Texture

The loam soil in Harvey 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

3
successive plantings in your 192-day season

Sow every 8 weeks. Last sowing by Jul 16 to harvest before frost.

Astilbe Water Budget

Plant needs
1.5″/week
Rainfall provides
0.5″/week
You supply
1.2″/week
Watering frequency 2-3 times/week
Season total 2,035 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 0.6" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.3" 0" ❄️ Dormant
Apr 6.5" 2.6" 3.9" 🚿 Regular watering
May 6.5" 3.7" 2.8" 💧 Light watering
Jun 6.5" 3.9" 2.6" 💧 Light watering
Jul 6.5" 2.7" 3.8" 🚿 Regular watering
Aug 6.5" 2.5" 4" 🚿 Regular watering
Sep 6.5" 2.3" 4.2" 🚿 Regular watering
Oct 6.5" 1.5" 5" 🚿 Regular watering
Nov 0.7" 0" ❄️ Dormant
Dec 0.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Harvey 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 3,504 GDD Excellent fit

Astilbe Planting Timeline — Harvey County, KS

Astilbe Planting Calendar

Activity When Date Range
Start Indoors February 11 Feb 11 – Feb 25
Transplant Outdoors April 22 Apr 22 – May 6
Bloom July 1 Jul 1 – Sep 9

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 · 2-3 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–8 · Your soil: ideal

🗺️ USDA Zone

Zone 6b

📆 Growing Season

192 days in Harvey County

Growing Tips for Astilbe in Harvey County

Direct sow Astilbe outdoors after April 15 in Harvey County when soil has warmed and frost danger has passed.

Harvey County receives only 23" 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 Harvey County, KS?

Harvey County is in Zone 6b with an average last frost of April 15. Plan your Astilbe planting based on this frost date — see the calendar above for exact timing.

What planting zone is Harvey County, KS?

Harvey County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 15 and first fall frost is October 24.

When should I plant Astilbe in Harvey County, KS?

In Harvey County, KS, plant Astilbe after the last frost (around April 15) and before the first frost (around October 24). Best results when soil holds above 50°F.

What growing zone is Harvey County, KS for Astilbe?

Harvey County sits in USDA Zone 6b. Astilbe grows reliably in zones 3a through 8b, so it's a good fit here.

Can Astilbe grow in Harvey County's climate?

Yes — Astilbe grows well in Harvey County's temperate climate. Harvey County averages a 192-day frost-free season, with last frost around April 15 and first frost around October 24.

🌱

Your Harvey County Garden Planner — Free

A 22-page printable planner built for Harvey 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 Harvey 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.