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When to plant Astilbe in Conception, MO

Plant Astilbe in Conception during the brief May 6–May 20 window. With 174 frost-free days, fall plantings can't mature before October 13.

When to Plant Astilbe in Conception, MO

Nodaway County, Missouri Zone 5b June

June in Nodaway County, Missouri — your action list

Each item below is timed to Nodaway County, Missouri's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 22
Avg. first frost October 13
Soil temp (4") 70°F
Watering Low
Pest pressure High
Daylight 14.9 hrs
  1. Fire up the seed-starting tray: astilbe

    You're about 15 weeks out from your last frost — the perfect window to get these germinating indoors.

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.

Conception, Missouri is in USDA Zone 5b. The average last spring frost is April 22 and the first fall frost is October 13, giving you a growing season of approximately 174 days.

At an elevation of 950 feet, Nodaway County receives approximately 42 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Astilbe to ensure they mature before fall.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Conception, MO (Zone 5b) Moderate season
174 days
Last Spring Frost April 22
174 growing days
First Fall Frost October 13

Conception Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.5

Drainage

Well Drained

Astilbe Planting Risk Windows

Early Start (70% safe) ✓ Fits season (13 days to spare)
Start indoors: Feb 11 Transplant: Apr 29 🌸 Bloom: Jul 15 – Sep 23
Recommended (50%) ✓ Fits season (13 days to spare)
Start indoors: Feb 18 Transplant: May 6 🌸 Bloom: Jul 22 – Sep 30
Safe Start (90%) ✓ Fits season (13 days to spare)
Start indoors: Mar 4 Transplant: May 20 🌸 Bloom: Aug 5 – Oct 14

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 Conception

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

Soil pH

Your soil pH (5.7–6.5) overlaps with Astilbe's range (6.0–8.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Astilbe.

Organic Matter

Organic matter is moderate (3.2%). 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 174-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
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 56 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 1.9" 0" ❄️ Dormant
Feb 2.1" 0" ❄️ Dormant
Mar 3" 0" ❄️ Dormant
Apr 6.5" 4.4" 2.1" 💧 Light watering
May 6.5" 4.8" 1.7" 💧 Light watering
Jun 6.5" 5.3" 1.2" 💧 Light watering
Jul 6.5" 4.1" 2.4" 💧 Light watering
Aug 6.5" 3.8" 2.7" 💧 Light watering
Sep 6.5" 4.1" 2.4" 💧 Light watering
Oct 6.5" 3.7" 2.8" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 2.4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Nodaway 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 ~1,041 GDD — county provides 2,131 GDD Excellent fit

Astilbe Planting Timeline — Conception, MO

Astilbe Planting Calendar

Activity When Date Range
Start Indoors February 18 Feb 18 – Mar 4
Transplant Outdoors May 6 May 6 – May 20
Bloom July 22 Jul 22 – Sep 30

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
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 · Only during dry spells

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–8 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

174 days in Nodaway County

Growing Tips for Astilbe in Conception

Direct sow Astilbe outdoors after April 22 in Nodaway 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 →

When should I plant Astilbe in Conception, MO?

In Conception, MO, plant Astilbe after the last frost (around April 22) and before the first frost (around October 13). Best results when soil holds above 50°F.

What growing zone is Conception, MO for Astilbe?

Conception sits in USDA Zone 5b. Astilbe grows reliably in zones 3a through 8b, so it's a good fit here.

Can Astilbe grow in Conception's climate?

Yes — Astilbe grows well in Conception's temperate climate. Conception averages a 174-day frost-free season, with last frost around April 22 and first frost around October 13.

🌱

Your Nodaway County Garden Planner — Free

A 22-page printable planner built for Nodaway County (Zone 5b). 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 Nodaway County, MO. Local conditions may vary. Last updated: June 2026.