When to plant Astilbe in Franklin County, ME
Franklin County's 137-day season only supports one Astilbe planting per year. Sow between May 28 and June 11 for the best chance at full maturity before September 28.
When to Plant Astilbe in Franklin County, ME
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.
Franklin County, Maine is in USDA Zone 5a. The average last spring frost is May 14 and the first fall frost is September 28, giving you a growing season of approximately 137 days.
At an elevation of 244 feet, Franklin County receives approximately 40.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Astilbe to ensure they mature before fall.
Franklin County Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-6.6
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 | — | 3.2" | 0" | ❄️ Dormant |
| Feb | — | 2.6" | 0" | ❄️ Dormant |
| Mar | — | 3.9" | 0" | ❄️ Dormant |
| Apr | — | 3.1" | 0" | ❄️ Dormant |
| May | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Jun | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Jul | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Aug | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Sep | 4.3" | 3" | 1.3" | 💧 Light watering |
| Oct | — | 3.4" | 0" | ❄️ Dormant |
| Nov | — | 2.7" | 0" | ❄️ Dormant |
| Dec | — | 3.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Franklin County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Astilbe Planting Timeline — Franklin County, ME
Astilbe Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 12 | Mar 12 – Mar 26 |
| Transplant Outdoors | May 28 | May 28 – Jun 11 |
| Bloom | August 13 | Aug 13 – Oct 15 |
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 | Transplant Outdoors |
| July | — |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| 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 5a
📆 Growing Season
137 days in Franklin County
Growing Tips for Franklin 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 Franklin County, ME?
Franklin County is in Zone 5a with an average last frost of May 14. Plan your Astilbe planting based on this frost date — see the calendar above for exact timing.
What planting zone is Franklin County, ME?
Franklin County, Maine is in USDA Hardiness Zone 5a. The average last spring frost is May 14 and first fall frost is September 28.
When should I plant Astilbe in Franklin County, ME?
In Franklin County, ME, plant Astilbe after the last frost (around May 14) and before the first frost (around September 28). Best results when soil holds above 50°F.
What growing zone is Franklin County, ME for Astilbe?
Franklin County sits in USDA Zone 5a. Astilbe grows reliably in zones 3a through 8b, so it's a good fit here.
Can Astilbe grow in Franklin County's climate?
Yes — Astilbe grows well in Franklin County's temperate climate. Franklin County averages a 137-day frost-free season, with last frost around May 14 and first frost around September 28.
Your Franklin County Garden Planner — Free
A 22-page printable planner built for Franklin County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.