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When to Plant Astilbe in Jack County, TX

Jack County, Texas Zone 8a June

Your June game plan for Jack County, Texas

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

Avg. last frost March 26
Avg. first frost November 9
Soil temp (4") 73°F
Watering Low
Pest pressure High
Daylight 14.2 hrs
  1. Collect astilbe at their peak

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

July prep starts now
  • 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.

Jack County, Texas is in USDA Zone 8a. The average last spring frost is March 26 and the first fall frost is November 9, giving you a growing season of approximately 228 days.

At an elevation of 2,081 feet, Jack County receives approximately 66.9 inches of rainfall annually with predominantly clay soil. Summer highs average 89°F, providing good warmth for Astilbe during the growing season. Clay soil retains moisture well for Astilbe, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Astilbe root diseases.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Jack County, TX (Zone 8a) Long season
228 days
Last Spring Frost March 26
228 growing days
First Fall Frost November 9
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Jack County Soil Profile

Soil Type

Clay

Soil pH

7.3-7.6

Drainage

Well Drained

Astilbe Planting Risk Windows

Early Start (70% safe) ✓ Fits season (109 days to spare)
Start indoors: Jan 22 Transplant: Mar 19 🌸 Bloom: May 28 – Jul 16
Recommended (50%) ✓ Fits season (109 days to spare)
Start indoors: Jan 29 Transplant: Mar 26 🌸 Bloom: Jun 4 – Jul 23
Safe Start (90%) ✓ Fits season (103 days to spare)
Start indoors: Feb 19 Transplant: Apr 16 🌸 Bloom: Jun 25 – Aug 13

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 Jack County

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

Soil pH

Your soil pH (7.3–7.6) is within Astilbe's preferred range (6.0–8.0).

Soil Texture

Heavy clay soil (42% clay) in Jack County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.

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

3
successive plantings in your 228-day season

Sow every 8 weeks. Last sowing by Aug 01 to harvest before frost.

Astilbe Water Budget

Plant needs
1.5″/week
Rainfall provides
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 2" 0" ❄️ Dormant
Feb 2.3" 0" ❄️ Dormant
Mar 6.5" 3.7" 2.8" 💧 Light watering
Apr 6.5" 8" 0" ✅ Rainfall sufficient
May 6.5" 9.7" 0" ✅ Rainfall sufficient
Jun 6.5" 9.6" 0" ✅ Rainfall sufficient
Jul 6.5" 8.5" 0" ✅ Rainfall sufficient
Aug 6.5" 7.6" 0" ✅ Rainfall sufficient
Sep 6.5" 6.7" 0" ✅ Rainfall sufficient
Oct 6.5" 4.3" 2.2" 💧 Light watering
Nov 6.5" 2.6" 3.9" 🚿 Regular watering
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Jack 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 ~1,424 GDD — county provides 3,819 GDD Excellent fit

Astilbe Planting Timeline — Jack County, TX

Astilbe Planting Calendar

Activity When Date Range
Start Indoors January 29 Jan 29 – Feb 12
Transplant Outdoors March 26 Mar 26 – Apr 9
Bloom June 4 Jun 4 – Jul 23

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

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–8 · Your soil: ideal

🗺️ USDA Zone

Zone 8a

📆 Growing Season

228 days in Jack County

Growing Tips for Astilbe in Jack County

Direct sow Astilbe outdoors after March 26 in Jack County when soil has warmed and frost danger has passed.

With Jack County's clay soil (42% clay), work in 3-4 inches of compost before planting Astilbe. Avoid tilling when soil is wet to prevent compaction.

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 Jack County, TX?

Jack County is in Zone 8a with an average last frost of March 26. Plan your Astilbe planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jack County, TX?

Jack County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 26 and first fall frost is November 9.

🌱

Your Jack County Garden Planner — Free

A 22-page printable planner built for Jack County (Zone 8a). 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 Jack County, TX. 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.