The Collaborative International Dictionary of English v.0.48:

chiggerflower \chiggerflower\ n.
   an erect perennial of eastern and southern U. S. (Asclepias
   tuberosa) having showy orange flowers.

   Syn: butterfly weed, orange milkweed, pleurisy root, tuber
        root, Indian paintbrush, Asclepias tuberosa.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

chiggerflower
    n 1: erect perennial of eastern and southern United States
         having showy orange flowers [syn: butterfly weed, orange
         milkweed, chigger flower, chiggerflower, pleurisy
         root, tuber root, Indian paintbrush, Asclepias
         tuberosa]