The Collaborative International Dictionary of English v.0.48:
Bramble bush \Bram"ble bush`\ (b[.u]sh`). (Bot.) The bramble, or a collection of brambles growing together. [1913 Webster] He jumped into a bramble bush And scratched out both his eyes. --Mother Goose. [1913 Webster]WordNet (r) 3.0 (2006):
bramble bush n 1: any prickly shrub of the genus Rubus bearing edible aggregate fruits