When to plant Astilbe in Gooding County, ID
Gooding County sits in cold Zone 7a. Plant Astilbe May 10–May 24 for the single annual harvest; the October 3 first frost closes the window.
When to Plant Astilbe in Gooding County, ID
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.
Gooding County, Idaho is in USDA Zone 7a. The average last spring frost is May 3 and the first fall frost is October 3, giving you a growing season of approximately 153 days.
At an elevation of 5,631 feet, Gooding County receives approximately 16.6 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Astilbe during the growing season. With low rainfall, drip irrigation is essential for growing Astilbe successfully. Mulch heavily to conserve soil moisture.
Gooding County Soil Profile
Soil Type
Loam
Soil pH
6.5-8.2
Drainage
Well Drained
Monthly Watering Guide for Astilbe
Astilbe needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Astilbe Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.2" | 0" | ❄️ Dormant |
| Feb | — | 0.9" | 0" | ❄️ Dormant |
| Mar | — | 1.4" | 0" | ❄️ Dormant |
| Apr | — | 2" | 0" | ❄️ Dormant |
| May | 4.3" | 2.2" | 2.1" | 💧 Light watering |
| Jun | 4.3" | 1.1" | 3.2" | 🚿 Regular watering |
| Jul | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Aug | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Sep | 4.3" | 1.2" | 3.1" | 🚿 Regular watering |
| Oct | 4.3" | 1.5" | 2.8" | 🚿 Regular watering |
| Nov | — | 1.1" | 0" | ❄️ Dormant |
| Dec | — | 1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Gooding County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Astilbe Planting Timeline — Gooding County, ID
Astilbe Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 1 | Mar 1 – Mar 15 |
| Transplant Outdoors | May 10 | May 10 – May 24 |
| Bloom | July 19 | Jul 19 – Sep 13 |
Plant 1.5" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors |
| June | — |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| 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
153 days in Gooding County
Growing Tips for Gooding 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 Gooding County, ID?
Gooding County is in Zone 7a with an average last frost of May 3. Plan your Astilbe planting based on this frost date — see the calendar above for exact timing.
What planting zone is Gooding County, ID?
Gooding County, Idaho is in USDA Hardiness Zone 7a. The average last spring frost is May 3 and first fall frost is October 3.
When should I plant Astilbe in Gooding County, ID?
In Gooding County, ID, plant Astilbe after the last frost (around May 3) and before the first frost (around October 3). Best results when soil holds above 50°F.
What growing zone is Gooding County, ID for Astilbe?
Gooding 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 Gooding County's climate?
Yes — Astilbe grows well in Gooding County's temperate climate. Gooding County averages a 153-day frost-free season, with last frost around May 3 and first frost around October 3.
Your Gooding County Garden Planner — Free
A 22-page printable planner built for Gooding 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.