False Lily-of-the-Valley
Maianthemum dilatatum
Asparagaceae · perennial · native
Last updated
Data Maturity Baseline
This profile contains verified botanical data. Regional field notes and expert review are in progress.
Field Observations
Field Observation
Maianthemum dilatatum · False Lily-of-the-Valley
new leaves
Quick Facts
Height
6-10 in
Spread
indefinite (rhizomatous)
Growth Rate
Moderate
Light
Partial Shade to Full Shade
Soil
Moist, Well Drained
Water
Moderate to high
Hardiness
Zone Zones 3–8
Origin
Western North America; Alaska to California, also eastern
Phenological Calendar
As of April 28, 2026, Puget Sound stations range from 1536.6 to 1694.7 GDD₃₂. False Lily-of-the-Valley has passed new leaves (1580 GDD₃₂).
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Apr 28, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 1,695 | new leaves | — | — |
| Seattle / UW | 1,654 | new leaves | — | — |
| Kent / Auburn | 1,644 | new leaves | — | — |
| Olympia / Tumwater | 1,603 | new leaves | — | — |
| Bellingham / Whatcom | 1,591 | new leaves | — | — |
| Tacoma / Puyallup | 1,572 | Pre-season | new leaves | 8 |
| Sequim / Rain Shadow | 1,537 | Pre-season | new leaves | 43 |
| Stage | GDD32 | Typical Window |
|---|---|---|
| ● new leaves BBCH 11 NOW | 1580 | April-May |
GDD = Growing Degree Days (base 32°F, Jan 1 start). Why base 32? Hover over GDD values for source details. Season tracker for Kent / Auburn as of Apr 28, 2026. Predicted dates use 16-day weather forecast through May 14, 2026, then climate normals.