Aesculus californica
Common name: 
California Buckeye
California Horsechestnut
ES-ku-lus kal-i-FORN-i-ka
Sapindaceae, Hippocastanaceae
Native to (or naturalized in) Oregon: 
  • Broadleaf deciduous tree or large shrub, single or multistemmed, 12-30ft (3.5-9 m) tall, flat topped to rounded and very broad; trunk short, with many ascending branches, bark grayish white.  Leaves opposite, palmately compound, 5 leaflets, occasionally 7, each 7.5-15 cm long, elliptic-oblong to lance-oblong, base narrowed or rounded, tip acuminate, margin sharply serrate, dark green above, paler below with hairs on veins; petiole 1-2.5 cm long.  Flowers showy, white to rose-colored, fragrant, about 2.5 cm long, in dense, narrow clusters, 8-20 cm long; stamens long-exserted, petals of equal length.  Fruit somewhat pear shaped, 5-7 cm long, usually contains 1 large seed, 2-5 cm, they are glossy brown and poisonous.
  • Sun, drought resistant, often summer deciduous in its native habitat, will retain leaves until fall if given supplemental irrigation.  All parts of the tree are toxic, honeybees are poisoned by the nectar and pollen.
  • Hardy to USDA Zone 7     Native to California, found in the woodlands and valleys of the Coast Range, Sierra Nevada and Tehachapi Mountains.
  • Portland, Oregon: Hoyt Arboretum.
  • Oregon State Univ. campus: east of Hovland Hall (2013)
Click image to enlarge
  • young developing flower spike (panicle) (S. Ruettgers)

    young developing flower spike (panicle) (S. Ruettgers)

  • plant habit, spring flowering

    plant habit, spring flowering

  • flower cluster and leaves

    flower cluster and leaves

  • flower cluster and flowers

    flower cluster and flowers

  • start of fruit development and young fruit

    start of fruit development and young fruit

  • plant habit, summer

    plant habit, summer

  • leaf


  • developing fruit cluster

    developing fruit cluster

  • plant habit, summer deciduous

    plant habit, summer deciduous

  • low tree habit, winter

    low tree habit, winter

  • shrub habit, winter

    shrub habit, winter

  • fruit


  • fruit and seeds

    fruit and seeds

  • buds


  • trunk, bark

    trunk, bark