When to plant Astilbe in Clark County, IN
Clark County sits in cold Zone 7a. Plant Astilbe April 17–May 1 for the single annual harvest; the October 22 first frost closes the window.
When to Plant Astilbe in Clark County, IN
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.
Clark County, Indiana is in USDA Zone 7a. The average last spring frost is April 10 and the first fall frost is October 22, giving you a growing season of approximately 195 days.
At an elevation of 1,265 feet, Clark County receives approximately 36.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Astilbe during the growing season.
Clark County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Astilbe Planting Timeline — Clark County, IN
Astilbe Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 6 | Feb 6 – Feb 20 |
| Transplant Outdoors | April 17 | Apr 17 – May 1 |
| Bloom | June 26 | Jun 26 – Aug 21 |
Plant 1.5" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | — |
| April | Transplant Outdoors |
| May | Transplant Outdoors |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
High — keep soil consistently moist
📅 Days to Maturity
70–100 days
🧪 Soil pH
Needs 6–8 · Your soil: N/A
🗺️ USDA Zone
Zone 7a
📆 Growing Season
195 days in Clark County
Growing Tips for Clark County
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 →
Astilbe in Other Locations
Frequently Asked Questions
When should I plant Astilbe in Clark County, IN?
Clark County is in Zone 7a with an average last frost of April 10. Plan your Astilbe planting based on this frost date — see the calendar above for exact timing.
What planting zone is Clark County, IN?
Clark County, Indiana is in USDA Hardiness Zone 7a. The average last spring frost is April 10 and first fall frost is October 22.
When should I plant Astilbe in Clark County, IN?
In Clark County, IN, plant Astilbe after the last frost (around April 10) and before the first frost (around October 22). Best results when soil holds above 50°F.
What growing zone is Clark County, IN for Astilbe?
Clark County sits in USDA Zone 7a. Astilbe grows reliably in zones 3a through 8b, so it's a good fit here.
Can Astilbe grow in Clark County's climate?
Yes — Astilbe grows well in Clark County's temperate climate. Clark County averages a 195-day frost-free season, with last frost around April 10 and first frost around October 22.
Your Clark County Garden Planner — Free
A 22-page printable planner built for Clark County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.