Spiraea thunbergii
Common name: 
Thunberg Spirea
Pronunciation: 
sp-i-RE-a thun-BER-je-i
Family: 
Rosaceae
Genus: 
Type: 
Broadleaf
Native to (or naturalized in) Oregon: 
No
  • Deciduous shrub, 3-5 ft (0.0-1.5 m) tall and wide, arching, willowy.   Leaves 25-40 mm long, narrow, only 3-6 mm wide (narrower than S. × arguta), sharply serrate, pale green.   Flowers are white, single, small (ca. 8 mm across), often on shorter shoots than on S. × arguta.
  • Sun to light shade. Not easy to distinguish S. thunbergii from S. × arguta; when in bloom, S. × arguta has very long unbranched shoots and those of S. thunbergii are shorter.  This difference can still be observed as bloom ends and shoot growth begins.
  • Hardy to USDA Zone 4      Native to Japan and China 
  • thunbergii: after Carl Peter Thunberg
  • Oregon State Univ. campus: east side of Milam, south end.
Click image to enlarge
  • plant habit, spring flowering

    plant habit, spring flowering

  • spring flowering

    spring flowering

  • flowering branches

    flowering branches

  • leaves and flowers

    leaves and flowers

  • plant habit, summer

    plant habit, summer

  • flowering branches, comparison

    flowering branches, comparison

  • comparison of shoots at end of flowering

    comparison of shoots at end of flowering