The Collaborative International Dictionary of English v.0.48:

Monocarpic \Mon`o*car"pic\, Monocarpous \Mon`o*car"pous\, a.
   [Mono- + Gr. ? fruit: cf. F. monocarpe.] (Bot.)
   Bearing fruit but once, and dying after fructification, as
   beans, maize, mustard, etc.
   [1913 Webster]

   Note: Annual and biennual herbs are monocarpic, so also some
         plants of longer duration, as the century plant.
         [1913 Webster]

WordNet (r) 3.0 (2006):

monocarpic
    adj 1: dying after bearing fruit only once