The Collaborative International Dictionary of English v.0.48:

Brambly \Bram"bly\, a.
   Pertaining to, resembling, or full of, brambles. "In brambly
   wildernesses." --Tennyson.
   [1913 Webster]

WordNet (r) 3.0 (2006):

brambly
    adj 1: covered with brambles and ferns and other undergrowth
           [syn: braky, brambly]