When to Plant Sedum (Stonecrop) in Whatcom County, WA
June in the garden — Whatcom County, Washington
A quick June briefing for Whatcom County, Washington gardeners — what's urgent, what's next, and what can wait.
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Time to start sedum (stonecrop) inside
Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.
Coming up in July — start thinking about
- First harvests: sedum (stonecrop)
Sedum (Hylotelephium spectabile, formerly Sedum spectabile) is a supremely tough, drought-tolerant perennial prized for its late-season interest. The flat-topped clusters of starry flowers open pink in late summer and deepen to copper-red as temperatures cool, remaining attractive well into fall and providing seed heads that feed birds through winter. Succulent foliage emerges blue-green in spring, is handsome all season, and turns bronzy after frost. Remarkably adaptable — thrives in poor, gravelly, or sandy soils where other perennials struggle — and virtually maintenance-free once established.
Whatcom County, Washington is in USDA Zone 8a. The average last spring frost is April 6 and the first fall frost is October 29, giving you a growing season of approximately 206 days.
At an elevation of 386 feet, Whatcom County receives approximately 49 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Sedum (Stonecrop) during the growing season.
Whatcom County Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-6.4
Drainage
Well Drained
Sedum (Stonecrop) Planting Risk Windows
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 Whatcom County
How your county's soil matches Sedum (Stonecrop)'s growing requirements.
Soil pH
Your soil pH (5.2–6.4) is more acidic than Sedum (Stonecrop) prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Whatcom County is excellent for Sedum (Stonecrop) — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.7%) — Sedum (Stonecrop) will thrive.
How to Plant Sedum (Stonecrop)
Succession Planting Sedum (Stonecrop)
Sow every 6.9 weeks. Last sowing by Jul 31 to harvest before frost.
Sedum (Stonecrop) Water Budget
Monthly Watering Guide for Sedum (Stonecrop)
Sedum (Stonecrop) needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.
| Month | Sedum (Stonecrop) Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 6.1" | 0" | ❄️ Dormant |
| Feb | — | 6.2" | 0" | ❄️ Dormant |
| Mar | — | 4.3" | 0" | ❄️ Dormant |
| Apr | 2.2" | 3.8" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 3.1" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 2.1" | 0.1" | 💧 Light watering |
| Jul | 2.2" | 0.7" | 1.5" | 🚿 Regular watering |
| Aug | 2.2" | 0.9" | 1.3" | 🚿 Regular watering |
| Sep | 2.2" | 2" | 0.2" | 💧 Light watering |
| Oct | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| Nov | — | 7.1" | 0" | ❄️ Dormant |
| Dec | — | 8.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Whatcom County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Sedum (Stonecrop) 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.
Sedum (Stonecrop) Planting Timeline — Whatcom County, WA
Sedum (Stonecrop) Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 9 | Feb 9 – Feb 23 |
| Transplant Outdoors | April 6 | Apr 6 – Apr 20 |
| Bloom | July 27 | Jul 27 – Oct 19 |
Plant 1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | — |
| April | Transplant Outdoors |
| May | — |
| June | — |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · Natural rainfall sufficient
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 8a
📆 Growing Season
206 days in Whatcom County
Growing Tips for Sedum (Stonecrop) in Whatcom County
Direct sow Sedum (Stonecrop) outdoors after April 06 in Whatcom County when soil has warmed and frost danger has passed.
General growing tips
Plant divisions or container plants in spring after frost danger passes, or in early fall. Excellent drainage is the primary requirement — upright border sedums will rot in wet, heavy soils over winter. Lean soil actually improves performance; avoid over-fertilizing which causes floppy stems. Tall cultivars (Autumn Joy, Matrona) may need light staking in rich soil. Divide every 3–4 years in spring when centers become sparse. Deadhead selectively — leaving seed heads through winter extends ornamental interest and feeds goldfinches. Very low water requirement once established. Year 2+ plants reach full clump size and peak bloom display.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Sedum (Stonecrop) in Other Locations
Frequently Asked Questions
When should I plant Sedum (Stonecrop) in Whatcom County, WA?
Whatcom County is in Zone 8a with an average last frost of April 6. Plan your Sedum (Stonecrop) planting based on this frost date — see the calendar above for exact timing.
What planting zone is Whatcom County, WA?
Whatcom County, Washington is in USDA Hardiness Zone 8a. The average last spring frost is April 6 and first fall frost is October 29.
Your Whatcom County Garden Planner — Free
A 22-page printable planner built for Whatcom County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.