GDD base 50 = 130 . We track GDD at http://agebb.missouri.edu/weather/reports/gddTable.asp and rate the phenology stages according to the Modified E-L System https://door.extension.wisc.edu/files/2010/10/ModifiedEichhornLorennzsystem.pdf

E-L Stage 4 Bud Burst

Genomics NC-6

E-L Stage 9 2 to 3 leaves separated; shoots 2-4 cm long

E-L Stage 11 4 Leaves Seperated

E-L Stage 12 5 Leaves separated; shoots about 10 cm long; inflorescence clear

E-L Stage 13 6 Leaves separated