The Collaborative International Dictionary of English v.0.48:

Hemstitch \Hem"stitch\, v. t. [imp. & p. p. Hemstitched; p.
   pr. & vb. n. Hemstitching.] [Hem + stitch.]
   To ornament at the head of a broad hem by drawing out a few
   parallel threads, and fastening the cross threads in
   successive small clusters; as, to hemstitch a handkerchief.
   [1913 Webster]

WordNet (r) 3.0 (2006):

hemstitching
    n 1: a stitch in which parallel threads are drawn and exposed
         threads are caught together in groups [syn: hemstitch,
         hemstitching]