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When to Plant Astilbe in Cape May County, NJ

Cape May County, New Jersey Zone 7b June

Your June gardening checklist

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Cape May County, New Jersey.

Avg. last frost March 29
Avg. first frost November 11
Soil temp (4") 78°F
Watering Low
Pest pressure High
Daylight 14.7 hrs
  1. Pick astilbe

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

To set up a strong July, finish these tasks
  • 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.

Cape May County, New Jersey is in USDA Zone 7b. The average last spring frost is March 29 and the first fall frost is November 11, giving you a growing season of approximately 227 days.

At an elevation of 928 feet, Cape May County receives approximately 44.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 94°F, providing good warmth for Astilbe during the growing season.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Cape May County, NJ (Zone 7b) Long season
227 days
Last Spring Frost March 29
227 growing days
First Fall Frost November 11

Cape May County Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.5

Drainage

Well Drained

Astilbe Planting Risk Windows

Early Start (70% safe) ✓ Fits season (94 days to spare)
Start indoors: Jan 20 Transplant: Mar 31 🌸 Bloom: Jun 9 – Aug 4
Recommended (50%) ✓ Fits season (94 days to spare)
Start indoors: Jan 25 Transplant: Apr 5 🌸 Bloom: Jun 14 – Aug 9
Safe Start (90%) ✓ Fits season (96 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 Cape May County

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

Soil pH

Your soil pH (4.9–6.5) is more acidic than Astilbe prefers (6.0–8.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Cape May 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 (3.1%). 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 227-day season

Sow every 8 weeks. Last sowing by Aug 03 to harvest before frost.

Astilbe Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 450 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 2.9" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 6.5" 3.5" 3" 💧 Light watering
Apr 6.5" 4.2" 2.3" 💧 Light watering
May 6.5" 4.2" 2.3" 💧 Light watering
Jun 6.5" 4.2" 2.3" 💧 Light watering
Jul 6.5" 3.8" 2.7" 💧 Light watering
Aug 6.5" 4.5" 2" 💧 Light watering
Sep 6.5" 4.1" 2.4" 💧 Light watering
Oct 6.5" 3.7" 2.8" 💧 Light watering
Nov 6.5" 3.2" 3.3" 🚿 Regular watering
Dec 3.4" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Cape May 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 ~1,742 GDD — county provides 4,653 GDD Excellent fit

Astilbe Planting Timeline — Cape May County, NJ

Astilbe Planting Calendar

Activity When Date Range
Start Indoors January 25 Jan 25 – Feb 8
Transplant Outdoors April 5 Apr 5 – Apr 19
Bloom June 14 Jun 14 – Aug 9

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 · Only during dry spells

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–8 · Your soil: too_acidic

🗺️ USDA Zone

Zone 7b

📆 Growing Season

227 days in Cape May County

Growing Tips for Astilbe in Cape May County

Direct sow Astilbe outdoors after March 29 in Cape May 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 Cape May County, NJ?

Cape May County is in Zone 7b with an average last frost of March 29. Plan your Astilbe planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cape May County, NJ?

Cape May County, New Jersey is in USDA Hardiness Zone 7b. The average last spring frost is March 29 and first fall frost is November 11.

🌱

Your Cape May County Garden Planner — Free

A 22-page printable planner built for Cape May 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 Cape May County, NJ. 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.