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Wisconsin Plant of the Week

Cephalanthus occidentalis L.

Rubiaceae (Coffee Family)

Common Name:

buttonbush

09/22/2002

Buttonbush is a native deciduous shrub with a rounded form and open-branched arching stems. It grows naturally in swamps and along shorelines that are saturated or inundated at least occasionally.  Flowering is reduced in the shade or in drier soils.  Buttonbush is a pioneer species, followed by willow and alder in the upper Midwest or by cypress and tupelo further south. 

Fragrant white flowers bloom in dense round heads, about 4 cm across, and on long stalks.  The flowers are tiny with petals joined to form four lobes, and have 4 stamens inside. Each flower has a single protruding style with a swollen tip so the flower head looks like a pin cushion.  Flowers bloom continuously from June through September and attract bees, butterflies and hummingbirds .

As the flowers fade, they turn red, and as the fruit ripens the styles fall off and round red seed heads remain on the plant into the winter. 

Leaves are opposite or occasionally in whorls of three, even on the same plant.  Leaves are oval, up to 10 cm long, with a smooth edge and pinnate veins.  Young twigs are 4-sided and brown with white vertical lenticels. 

Buttonbush is easily propagated by seed and cuttings.  Unrooted cuttings pushed into moist soil can be used for shoreline erosion control. Buttonbush seeds are a prime food for many waterfowl and dense stands of the shrub are good cover for wetland birds.

  • Origin of the name: Cephalanthus, Gk., kephalo, head; occidentalis, L., western, refers to it being native to the western hemisphere unlike all others in this genus.
  • Range:  Eastern Canada, s. to Mexico and the West Indies
  • WI Range:  More common south of the Tension Zone, especially along large rivers
  • Common associates: red maple, ash, viburnum
  • Wetland Indicator Status: OBL
  • Coefficient of Conservatism: 9, WI; 7, MI; 5, Chicago Region
  • Related sites: WI State Herbarium; VT Dendrology
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