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When to Plant Astilbe in Haskell County, OK

Haskell County, Oklahoma Zone 7b July

July to-do list for Haskell County, Oklahoma

A quick July briefing for Haskell County, Oklahoma gardeners — what's urgent, what's next, and what can wait.

Avg. last frost March 28
Avg. first frost November 3
Soil temp (4") 86°F
Watering Low
Pest pressure High
Daylight 14.2 hrs
  1. Basket week: astilbe

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

Looking ahead to August
  • 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.

Haskell County, Oklahoma is in USDA Zone 7b. The average last spring frost is March 28 and the first fall frost is November 3, giving you a growing season of approximately 220 days.

At an elevation of 691 feet, Haskell County receives approximately 29.2 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
Haskell County, OK (Zone 7b) Long season
220 days
Last Spring Frost March 28
220 growing days
First Fall Frost November 3

Haskell County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.5

Drainage

Well Drained

Astilbe Planting Risk Windows

Early Start (70% safe) ✓ Fits season (87 days to spare)
Start indoors: Jan 17 Transplant: Mar 28 🌸 Bloom: Jun 6 – Aug 1
Recommended (50%) ✓ Fits season (87 days to spare)
Start indoors: Jan 24 Transplant: Apr 4 🌸 Bloom: Jun 13 – Aug 8
Safe Start (90%) ✓ Fits season (90 days to spare)
Start indoors: Feb 10 Transplant: Apr 21 🌸 Bloom: Jun 30 – Aug 25

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 Haskell County

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

Soil pH

Your soil pH (6.5–7.5) is within Astilbe's preferred range (6.0–8.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — 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 220-day season

Sow every 8 weeks. Last sowing by Jul 26 to harvest before frost.

Astilbe Water Budget

Plant needs
1.5″/week
Rainfall provides
0.6″/week
You supply
1.1″/week
Watering frequency 2-3 times/week
Season total 2,215 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 0.7" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 6.5" 1.9" 4.6" 🚿 Regular watering
Apr 6.5" 2.9" 3.6" 🚿 Regular watering
May 6.5" 4" 2.5" 💧 Light watering
Jun 6.5" 4.8" 1.7" 💧 Light watering
Jul 6.5" 3.8" 2.7" 💧 Light watering
Aug 6.5" 3" 3.5" 🚿 Regular watering
Sep 6.5" 3.1" 3.4" 🚿 Regular watering
Oct 6.5" 2.1" 4.4" 🚿 Regular watering
Nov 6.5" 1" 5.5" 🚿 Regular watering
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Haskell 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 4,015 GDD Excellent fit

Astilbe Planting Timeline — Haskell County, OK

Astilbe Planting Calendar

Activity When Date Range
Start Indoors January 24 Jan 24 – Feb 7
Transplant Outdoors April 4 Apr 4 – Apr 18
Bloom June 13 Jun 13 – Aug 8

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: ideal

🗺️ USDA Zone

Zone 7b

📆 Growing Season

220 days in Haskell County

Growing Tips for Astilbe in Haskell County

Direct sow Astilbe outdoors after March 28 in Haskell 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 Haskell County, OK?

Haskell County is in Zone 7b with an average last frost of March 28. Plan your Astilbe planting based on this frost date — see the calendar above for exact timing.

What planting zone is Haskell County, OK?

Haskell County, Oklahoma is in USDA Hardiness Zone 7b. The average last spring frost is March 28 and first fall frost is November 3.

🌱

Your Haskell County Garden Planner — Free

A 22-page printable planner built for Haskell 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 Haskell County, OK. Local conditions may vary. Last updated: July 2026.

Sources & credits

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