The Collaborative International Dictionary of English v.0.48:

candyweed \can"dy*weed`\ (k[a^]n"d[-e]*w[=e]d`), n.
   bog plant (Polygala lutea) of pine barrens of southeastern
   U.S. having spikes of irregular yellow-orange flowers.

   Syn: orange milkwort, yellow milkwort, yellow bachelor's
        button.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Polygala lutea
    n 1: bog plant of pine barrens of southeastern United States
         having spikes of irregular yellow-orange flowers [syn:
         orange milkwort, yellow milkwort, candyweed, yellow
         bachelor's button, Polygala lutea]