GDD base 50 accumulated since April 1 = +23 (+23 departure from normal) at Mountain Grove http://agebb.missouri.edu/weather/reports/gddTable.asp
Add March 2012: 23+306 = 329
Phenology stages according to the Modified E-L system http://door.uwex.edu/files/2010/10/ModifiedEichhornLorennzsystem.pdf