The Collaborative International Dictionary of English v.0.48:

hollygrape \hollygrape\ n.
   An ornamental evergreen shrub (Mahonia aquifolium) of the
   Pacific coast of North America having dark green pinnate
   leaves and racemes of yellow flowers followed by blue-black
   berries.

   Syn: Oregon grape, Oregon holly grape, mountain grape,
        holly-leaves barberry, Mahonia aquifolium.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

hollygrape
    n 1: ornamental evergreen shrub of Pacific coast of North
         America having dark green pinnate leaves and racemes of
         yellow flowers followed by blue-black berries [syn: Oregon
         grape, Oregon holly grape, hollygrape, mountain
         grape, holly-leaves barberry, Mahonia aquifolium]