The Collaborative International Dictionary of English v.0.48:

Staggerbush \Stag"ger*bush`\ (-b[.u]sh`), n. (Bot.)
   An American shrub (Andromeda Mariana) having clusters of
   nodding white flowers. It grows in low, sandy places, and is
   said to poison lambs and calves. --Gray.
   [1913 Webster]

WordNet (r) 3.0 (2006):

staggerbush
    n 1: deciduous shrub of coastal plain of the eastern United
         States having nodding pinkish-white flowers; poisonous to
         stock [syn: staggerbush, stagger bush, Lyonia
         mariana]