The Collaborative International Dictionary of English v.0.48:

Siberian \Si*be"ri*an\, a. [From Siberia, Russ. Sibire.]
   Of or pertaining to Siberia, a region comprising all northern
   Asia and belonging to Russia; as, a Siberian winter. -- n. A
   native or inhabitant of Siberia.
   [1913 Webster]

   Siberian crab (Bot.), the Siberian crab apple. See Crab
      apple, under Crab.

   Siberian dog (Zool.), one of a large breed of dogs having
      erect ears and the hair of the body and tail very long. It
      is distinguished for endurance of fatigue when used for
      the purpose of draught.

   Siberian pea tree (Bot.), a small leguminous tree (Cragana
      arborescens) with yellow flowers. It is a native of
      Siberia.
      [1913 Webster] Sibilance

WordNet (r) 3.0 (2006):

Siberian pea tree
    n 1: large spiny shrub of eastern Asia having clusters of yellow
         flowers; often cultivated in shelterbelts and hedges [syn:
         Siberian pea tree, Caragana arborescens]