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Sweet Mockorange

Philadelphus coronarius

Hydrangeaceae · [VERIFY] · introduced

Last updated

Data Coverage 3 of 6 dimensions
Site Data
Threats
Cultivars
Phenology
GDD Thresholds
Puget Sound

Philadelphus coronarius (Hydrangeaceae) is a deciduous shrub native to southeastern Europe and western Asia. It grows 6 to 10 feet tall with an upright, arching habit. In late spring, clusters of intensely fragrant white flowers (about 1 inch across) cover the plant. The fragrance is considered among the finest of any temperate shrub.

Sweet mockorange grows in full sun to part shade on a range of well-drained soils. It blooms on old wood, so pruning should follow flowering. The species is vigorous and may become leggy without periodic renewal pruning (removing oldest canes at ground level). No serious pest or disease problems are typical.

Quick Facts

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Hardiness
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Origin
southeastern Europe, Asia Minor

Phenological Calendar

Regional Season Tracker

GDD₃₂ accumulation across 7 Puget Sound stations · as of Mar 30, 2026
Station GDD₃₂ Current Stage Next To Go
Issaquah / East King 1,116 Pre-season Beginning of flowering 716
Seattle / UW 1,112 Pre-season Beginning of flowering 720
Olympia / Tumwater 1,049 Pre-season Beginning of flowering 784
Kent / Auburn 1,048 Pre-season Beginning of flowering 784
Bellingham / Whatcom 1,041 Pre-season Beginning of flowering 791
Tacoma / Puyallup 1,017 Pre-season Beginning of flowering 815
Sequim / Rain Shadow 1,012 Pre-season Beginning of flowering 820
Stage GDD32 Typical Window
Beginning of flowering BBCH 61 NEXT 1832 est. May 9 (avg)
Full bloom BBCH 65 2438 est. Jun 3 (avg)
Range: 1435–1648 GDD₃₂ (6yr)

GDD = Growing Degree Days (base 32°F, Jan 1 start). Why base 32? Source GDD₅₀ thresholds from Herms 2004 (OSU, Secrest Arboretum, Ohio) and UMD IPMnet (Gill & Klick, mid-Atlantic), converted to GDD₃₂ via Kent bloom-date mapping. Season tracker for Kent / Auburn as of Mar 30, 2026. Predicted dates use 16-day weather forecast through Apr 15, 2026, then climate normals.