American Bittersweet

Celastrus scandens

Celastraceae · vine groundcover · introduced

Last updated March 8, 2026

Data Coverage 2 of 6 dimensions

Site Data

Threats

Cultivars

Phenology

GDD Thresholds

Puget Sound

Quick Facts

Height

20 ft

Growth Rate

Fast

Light

Part Shade

Soil

Adaptable

Water

High

Hardiness

Zone Zones 2a–8b

Bloom Time

May to June

Fall Color

Yellow

Origin

Canada, New Brunswick, Quebec to Manitoba, and most of the U

Stage	Typical Window	What to Look For
Bud break BBCH 07	Feb 15-Mar 15	Buds swelling and beginning to open; first green tissue visible
Leaf emergence BBCH 11	Mar 1-Apr 1	First leaves fully unfurled on new growth
Bloom start BBCH 61	Mar 15-May 15	First open flowers visible; flowers white
Bloom end / petal fall BBCH 69	Apr 15-May 31	Last petals falling; flower structures fading
Fruit/seed development BBCH 71	Jun 1-Aug 31	Fruit or seed structures forming; fruit color: orange
Fruit/seed maturity BBCH 85	Sep 1-Nov 30	Fruit fully colored and ripened; seed dispersal may begin
Fall color / leaf senescence BBCH 93	Oct 1-Nov 15	Leaves changing color; fall display beginning
Dormancy BBCH 97	Nov 15-Feb 28	Leafless; no active growth; dormant buds set