Buttonbush

Cephalanthus occidentalis

Rubiaceae · broadleaf deciduous shrub · introduced

Last updated April 25, 2026

Quick Facts

Height

3–6 ft

Spread

3-6 ft

Growth Rate

Moderate

Light

Part Shade

Soil

Wet Tolerant

Water

High

Hardiness

Zone Zones 4a–8b

Bloom Time

June

Fall Color

Yellow

Aecial Stage (Alternate Host)

CarpenterwormModerate

Overwintering Larvae (Years 2-3)

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	Jun 15-Aug 15	First open flowers visible; flowers white
Bloom end / petal fall BBCH 69	Jul 15-Aug 31	Last petals falling; flower structures fading
Fruit/seed development BBCH 71	Sep 1-Nov 30	Fruit or seed structures forming; fruit color: white
Leaf drop BBCH 93	Oct 15-Nov 30	Leaves yellowing and dropping; no significant fall color display
Dormancy BBCH 97	Nov 15-Feb 28	Leafless; no active growth; dormant buds set

Data Maturity

Baseline Extension data. Expert review underway.