The Collaborative International Dictionary of English v.0.48:

minniebush \minniebush\ n.
   A low shrub (Menziesia pilosa) of the eastern U. S. with
   downy twigs.

   Syn: minnie bush, Menziesia pilosa.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Menziesia pilosa
    n 1: low shrub of the eastern United States with downy twigs
         [syn: minniebush, minnie bush, Menziesia pilosa]