When to Plant Hydrangeas in Campbell County, WY
Hydrangeas (Hydrangea spp.) are among the most spectacular summer-blooming shrubs, with large mophead, lacecap, or panicle flower clusters lasting weeks in the garden and drying beautifully for arrangements. Native to Asia and North America alike, the genus spans several garden species with different hardiness and blooming habits. Panicle hydrangeas (H. paniculata, e.g., Limelight) are the most cold-hardy (Zone 3) and most reliable bloomers; smooth hydrangeas (H. arborescens, e.g., Annabelle) are equally tough. Bigleaf hydrangeas (H. macrophylla) are prized for blue/pink color-shifting blooms but require reliable snow cover or winter protection in Zones 5–6. Flower color in macrophylla types is determined by soil pH (acidic = blue, alkaline = pink).
Campbell County, Wyoming is in USDA Zone 5a. The average last spring frost is May 20 and the first fall frost is September 20, giving you a growing season of approximately 123 days.
At an elevation of 8,132 feet, Campbell County receives approximately 22.3 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Hydrangeas to ensure they mature before fall.
Campbell County Soil Profile
Soil Type
Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Hydrangeas Planting Timeline — Campbell County, WY
Hydrangeas Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 11 | Mar 11 – Mar 25 |
| Transplant Outdoors | June 3 | Jun 3 – Jun 17 |
| Bloom | August 19 | Aug 19 – Nov 4 |
Plant 1" deep · 48" apart · Rows 60" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | — |
| June | Transplant Outdoors |
| July | — |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | Bloom |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
90–150 days
🧪 Soil pH
Needs 5.5–6.5 · Your soil: N/A
🗺️ USDA Zone
Zone 5a
📆 Growing Season
123 days in Campbell County
Growing Tips for Campbell County
Plant container-grown specimens in spring or fall, spacing at least 3–5 feet apart to allow for mature shrub spread. Most hydrangeas prefer morning sun with afternoon shade, especially in Zones 7+. Keep consistently moist — the name derives from the Greek for water vessel. Prune panicle and smooth types in late winter/early spring (they bloom on new wood). Prune bigleaf types only lightly after bloom; cutting stems in fall removes next year's buds. In Zone 5–6, protect bigleaf varieties with burlap or wire cages filled with leaves over winter. Fall planting (Zones 5+) gives excellent root establishment before summer heat. Year 2+ plants reach full size and bloom.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Hydrangeas in Other Locations
Frequently Asked Questions
When should I plant Hydrangeas in Campbell County, WY?
Campbell County is in Zone 5a with an average last frost of May 20. Plan your Hydrangeas planting based on this frost date — see the calendar above for exact timing.
What planting zone is Campbell County, WY?
Campbell County, Wyoming is in USDA Hardiness Zone 5a. The average last spring frost is May 20 and first fall frost is September 20.
Your Campbell County Garden Planner — Free
A 22-page printable planner built for Campbell 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.