Tuliptree
Full bloomLiriodendron tulipifera
Magnoliaceae · broadleaf deciduous tree · introduced
Last updated
Liriodendron tulipifera (Magnoliaceae) is a fast-growing deciduous tree native to eastern North America. It is one of the tallest eastern hardwoods, reaching 120 feet tall and 39 feet wide, with about 50 feet of growth in the first 20 years. The distinctively shaped leaves have four lobes and a flat or notched apex. Tulip-shaped yellow-green flowers with an orange band at the base appear in May to June but are often obscured by foliage on mature trees.
Tuliptree adapts to a range of soils but prefers moist, slightly acidic conditions (pH 4.5 to 6.5) in full sun. Bloom begins around 490 to 509 GDD (base 50 F). The tuliptree aphid is a serious pest, producing copious honeydew that leads to sooty mold on anything beneath the canopy. Verticillium wilt is also documented. Cultivars include 'Fastigiatum' (columnar), 'Aureo Marginatum' (yellow-edged leaves), and 'JFS-Oz' (compact). It is the official state tree of three U.S. states. Hardy in Zones 5a to 8b.
Plant Profile
Size & Form
Site Requirements
Ornamental Interest
Field Observations
Root Colonization Period
Diseases: Regionally Documented (1)
Pests: Regionally Documented (1)
Phenological Calendar
As of June 3, 2026, Puget Sound stations range from 2435.5 to 2672.8 GDD₃₂. Tuliptree has passed full bloom (1934 GDD₃₂).
Regional Season Tracker
GDD₃₂ accumulation across 7 Puget Sound stations · as of Jun 3, 2026| Station | GDD₃₂ | Current Stage | Next | To Go |
|---|---|---|---|---|
| Issaquah / East King | 2,673 | Full bloom | — | — |
| Kent / Auburn | 2,665 | Full bloom | — | — |
| Seattle / UW | 2,610 | Full bloom | — | — |
| Olympia / Tumwater | 2,570 | Full bloom | — | — |
| Tacoma / Puyallup | 2,535 | Full bloom | — | — |
| Bellingham / Whatcom | 2,533 | Full bloom | — | — |
| Sequim / Rain Shadow | 2,436 | Full bloom | — | — |
View full calendar (9 stages)
| Stage | GDD32 | Typical Window |
|---|---|---|
| Bloom start BBCH 61 | 1862 | Apr 1-Apr 30 |
| ● Full bloom BBCH 65 NOW | 1934 | — |
| Bud break BBCH 07 | — | Feb 15-Mar 15 |
| Leaf emergence BBCH 11 | — | Mar 1-Apr 1 |
| Bloom end / petal fall BBCH 69 | — | Apr 15-May 15 |
| Fruit/seed development BBCH 71 | — | Jun 1-Aug 31 |
| Fall color / leaf senescence BBCH 93 | — | Oct 1-Nov 15 |
| Dormancy BBCH 97 | — | Nov 15-Feb 28 |
| new leaves BBCH 11 | — Observed | — |
Sources: USDA Plants Database (seasonal estimate) ; UMD phenology catalog (UMD: extension.umd.edu) About GDD₃₂ →
Season tracker for Kent / Auburn as of Jun 3, 2026. Predicted dates use 16-day weather forecast through Jun 19, 2026, then climate normals.