The Collaborative International Dictionary of English v.0.48:

Heather \Heath"er\ (h[e^][th]"[~e]r; 277. This is the only
   pronunciation in Scotland), n. [See Heath.]
   Heath. [Scot.]
   [1913 Webster]

         Gorse and grass
         And heather, where his footsteps pass,
         The brighter seem.                       --Longfellow.
   [1913 Webster]

   Heather bell (Bot.), one of the pretty subglobose flowers
      of two European kinds of heather (Erica Tetralix, and
      Erica cinerea).
      [1913 Webster]

WordNet (r) 3.0 (2006):

heather bell
    n 1: common low European shrub with purple-red flowers [syn:
         bell heather, heather bell, fine-leaved heath, Erica
         cinerea]