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When to plant Astilbe in Fulton County, KY

Fulton County sits in cold Zone 7b. Plant Astilbe April 6–April 20 for the single annual harvest; the October 31 first frost closes the window.

When to Plant Astilbe in Fulton County, KY

Fulton County, Kentucky Zone 7b August

What to do in August

Your garden in Fulton County, Kentucky is working on a schedule, even when you're not. Here's where you should be this August.

Avg. last frost March 30
Avg. first frost October 31
Soil temp (4") 80°F
Watering Low
Pest pressure High
Daylight 13.4 hrs
  1. Basket week: astilbe

    If you can't use it all right away, check the food-preservation section of your planner.

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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.

Fulton County, Kentucky is in USDA Zone 7b. The average last spring frost is March 30 and the first fall frost is October 31, giving you a growing season of approximately 215 days.

At an elevation of 3,261 feet, Fulton County receives approximately 42.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 92°F, providing good warmth for Astilbe during the growing season.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Fulton County, KY (Zone 7b) Long season
215 days
Last Spring Frost March 30
215 growing days
First Fall Frost October 31

Fulton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.8

Drainage

Well Drained

Astilbe Planting Risk Windows

Early Start (70% safe) ✓ Fits season (84 days to spare)
Start indoors: Jan 18 Transplant: Mar 29 🌸 Bloom: Jun 7 – Aug 2
Recommended (50%) ✓ Fits season (82 days to spare)
Start indoors: Jan 26 Transplant: Apr 6 🌸 Bloom: Jun 15 – Aug 10
Safe Start (90%) ✓ Fits season (87 days to spare)
Start indoors: Feb 12 Transplant: Apr 23 🌸 Bloom: Jul 2 – Aug 27

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 Fulton County

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

Soil pH

Your soil pH (5.7–6.8) overlaps with Astilbe's range (6.0–8.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.9%). 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 215-day season

Sow every 8 weeks. Last sowing by Jul 23 to harvest before frost.

Astilbe Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,547 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 3.8" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 6.5" 4.3" 2.2" 💧 Light watering
Apr 6.5" 3.4" 3.1" 💧 Light watering
May 6.5" 3.6" 2.9" 💧 Light watering
Jun 6.5" 3.8" 2.7" 💧 Light watering
Jul 6.5" 4.4" 2.1" 💧 Light watering
Aug 6.5" 4.3" 2.2" 💧 Light watering
Sep 6.5" 3.2" 3.3" 🚿 Regular watering
Oct 6.5" 2.4" 4.1" 🚿 Regular watering
Nov 3.3" 0" ❄️ Dormant
Dec 2.9" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Oct in Fulton 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 ~1,615 GDD — county provides 4,085 GDD Excellent fit

Astilbe Planting Timeline — Fulton County, KY

Astilbe Planting Calendar

Activity When Date Range
Start Indoors January 26 Jan 26 – Feb 9
Transplant Outdoors April 6 Apr 6 – Apr 20
Bloom June 15 Jun 15 – Aug 10

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors
March
April Transplant Outdoors
May
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: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

215 days in Fulton County

Growing Tips for Astilbe in Fulton County

Direct sow Astilbe outdoors after March 30 in Fulton 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 Fulton County, KY?

Fulton County is in Zone 7b with an average last frost of March 30. Plan your Astilbe planting based on this frost date — see the calendar above for exact timing.

What planting zone is Fulton County, KY?

Fulton County, Kentucky is in USDA Hardiness Zone 7b. The average last spring frost is March 30 and first fall frost is October 31.

When should I plant Astilbe in Fulton County, KY?

In Fulton County, KY, plant Astilbe after the last frost (around March 30) and before the first frost (around October 31). Best results when soil holds above 50°F.

What growing zone is Fulton County, KY for Astilbe?

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

Can Astilbe grow in Fulton County's climate?

Yes — Astilbe grows well in Fulton County's temperate climate. Fulton County averages a 215-day frost-free season, with last frost around March 30 and first frost around October 31.

🌱

Your Fulton County Garden Planner — Free

A 22-page printable planner built for Fulton County (Zone 7b). 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 Fulton County, KY. Local conditions may vary. Last updated: August 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.