Blog

When to plant Astilbe in Stevens County County,

Stevens County County's short 179-day growing season means one Astilbe planting between April 27 and May 11. No fall crop in Zone 6b.

When to Plant Astilbe in Stevens County, KS

Stevens County, Kansas Zone 6b June

What to do in June

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

Avg. last frost April 20
Avg. first frost October 16
Soil temp (4") 74°F
Watering High
Pest pressure High
Daylight 14.5 hrs
  1. Fire up the seed-starting tray: astilbe

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

To set up a strong July, finish these tasks
  • First harvests: astilbe

Instant PDF download. No spam, unsubscribe any time.

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.

Stevens County, Kansas is in USDA Zone 6b. The average last spring frost is April 20 and the first fall frost is October 16, giving you a growing season of approximately 179 days.

At an elevation of 1,123 feet, Stevens County receives approximately 31.9 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Astilbe during the growing season.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Stevens County, KS (Zone 6b) Moderate season
179 days
Last Spring Frost April 20
179 growing days
First Fall Frost October 16

Stevens County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.8

Drainage

Well Drained

Astilbe Planting Risk Windows

Early Start (70% safe) ✓ Fits season (34 days to spare)
Start indoors: Feb 11 Transplant: Apr 22 🌸 Bloom: Jul 1 – Sep 9
Recommended (50%) ✓ Fits season (32 days to spare)
Start indoors: Feb 16 Transplant: Apr 27 🌸 Bloom: Jul 6 – Sep 14
Safe Start (90%) ✓ Fits season (33 days to spare)
Start indoors: Mar 2 Transplant: May 11 🌸 Bloom: Jul 20 – Sep 28

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 Stevens County

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

Soil pH

Your soil pH (6.5–7.8) is within Astilbe's preferred range (6.0–8.0).

Soil Texture

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

Drainage

Astilbe is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Astilbe.

How to Plant Astilbe

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

Succession Planting Astilbe

2
successive plantings in your 179-day season

Sow every 8 weeks. Last sowing by Jul 08 to harvest before frost.

Astilbe Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
1.4″/week
Watering frequency 2-3 times/week
Season total 2,297 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 2.4" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 6.5" 3.1" 3.4" 🚿 Regular watering
May 6.5" 3.9" 2.6" 💧 Light watering
Jun 6.5" 2.5" 4" 🚿 Regular watering
Jul 6.5" 2.7" 3.8" 🚿 Regular watering
Aug 6.5" 3" 3.5" 🚿 Regular watering
Sep 6.5" 2.5" 4" 🚿 Regular watering
Oct 6.5" 2.8" 3.7" 🚿 Regular watering
Nov 2.4" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Stevens 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 ~1,232 GDD — county provides 2,595 GDD Excellent fit

Astilbe Planting Timeline — Stevens County, KS

Astilbe Planting Calendar

Activity When Date Range
Start Indoors February 16 Feb 16 – Mar 2
Transplant Outdoors April 27 Apr 27 – May 11
Bloom July 6 Jul 6 – Sep 14

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
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

179 days in Stevens County

Growing Tips for Astilbe in Stevens County

Direct sow Astilbe outdoors after April 20 in Stevens 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 Stevens County, KS?

Stevens County is in Zone 6b with an average last frost of April 20. Plan your Astilbe planting based on this frost date — see the calendar above for exact timing.

What planting zone is Stevens County, KS?

Stevens County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 20 and first fall frost is October 16.

When should I plant Astilbe in Stevens County County, ?

In Stevens County County, , plant Astilbe after the last frost (around April 20) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is Stevens County County, for Astilbe?

Stevens County 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 Stevens County County's climate?

Yes — Astilbe grows well in Stevens County County's temperate climate. Stevens County County averages a 179-day frost-free season, with last frost around April 20 and first frost around October 16.

🌱

Your Stevens County Garden Planner — Free

A 22-page printable planner built for Stevens 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Stevens 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.