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When to plant Astilbe in Lyon County County,

In Lyon County County, Astilbe is a single-season spring crop — there's no second fall window. Plant May 18–June 1 for an 100-day harvest, finishing well before the October 2 first frost.

When to Plant Astilbe in Lyon County, MN

Lyon County, Minnesota Zone 5a June

Your June planting checklist for Lyon County, Minnesota

If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 4
Avg. first frost October 2
Soil temp (4") 64°F
Watering Low
Pest pressure High
Daylight 15.3 hrs
July prep starts now
  • Starting indoors: 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.

Lyon County, Minnesota is in USDA Zone 5a. The average last spring frost is May 4 and the first fall frost is October 2, giving you a growing season of approximately 151 days.

At an elevation of 634 feet, Lyon County receives approximately 35.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°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
Lyon County, MN (Zone 5a) Moderate season
151 days
Last Spring Frost May 4
151 growing days
First Fall Frost October 2
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Lyon County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7.2

Drainage

Well Drained

Astilbe Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 24 Transplant: May 12 🌸 Bloom: Jul 28 – Sep 29
Recommended (50%) ✗ May not fit
Start indoors: Mar 2 Transplant: May 18 🌸 Bloom: Aug 3 – Oct 5
Safe Start (90%) ✗ May not fit
Start indoors: Mar 13 Transplant: May 29 🌸 Bloom: Aug 14 – Oct 16

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 Lyon County

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

Soil pH

Your soil pH (5.8–7.2) overlaps with Astilbe's range (6.0–8.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.5%) — Astilbe will thrive.

How to Plant Astilbe

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

Succession Planting Astilbe

2
successive plantings in your 151-day season

Sow every 8 weeks. Last sowing by Jun 24 to harvest before frost.

Astilbe Water Budget

Plant needs
1.5″/week
Rainfall provides
1.0″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 674 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 1.3" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 3.8" 0" ❄️ Dormant
May 6.5" 4.5" 2" 💧 Light watering
Jun 6.5" 4.1" 2.4" 💧 Light watering
Jul 6.5" 3.6" 2.9" 💧 Light watering
Aug 6.5" 3.4" 3.1" 💧 Light watering
Sep 6.5" 3.2" 3.3" 🚿 Regular watering
Oct 6.5" 2.9" 3.6" 🚿 Regular watering
Nov 2.8" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Lyon 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 ~978 GDD — county provides 1,736 GDD Excellent fit

Astilbe Planting Timeline — Lyon County, MN

Astilbe Planting Calendar

Activity When Date Range
Start Indoors March 2 Mar 2 – Mar 16
Transplant Outdoors May 18 May 18 – Jun 1
Bloom August 3 Aug 3 – Oct 5

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors
June Transplant Outdoors
July
August Bloom
September Bloom
October Bloom
November
December
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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: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

151 days in Lyon County

Growing Tips for Astilbe in Lyon County

Direct sow Astilbe outdoors after May 04 in Lyon 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 Lyon County, MN?

Lyon County is in Zone 5a with an average last frost of May 4. Plan your Astilbe planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lyon County, MN?

Lyon County, Minnesota is in USDA Hardiness Zone 5a. The average last spring frost is May 4 and first fall frost is October 2.

When should I plant Astilbe in Lyon County, ?

In Lyon County, , plant Astilbe after the last frost (around May 4) and before the first frost (around October 2). Best results when soil holds above 50°F.

What growing zone is Lyon County, for Astilbe?

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

Can Astilbe grow in Lyon County's climate?

Yes — Astilbe grows well in Lyon County's temperate climate. Lyon County averages a 151-day frost-free season, with last frost around May 4 and first frost around October 2.

🌱

Your Lyon County Garden Planner — Free

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

Sources & credits

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