GDD base 50 accumulation for May 21 = 487 http://agebb.missouri.edu/weather/reports/gddTable.asp
Phenology stages according to the Modified E-L System http://door.uwex.edu/files/2010/10/ModifiedEichhornLorennzsystem.pdf
Some cultivars have begun flowering.
N Norton E-L Stage 16 10 leaves separated.
G Norton E-L Stage 16 10 leaves separated.
G Cabernet Sauvignon E-L Stage 15 8 leaves separated, shoot elongating rapidly; single flowers in compact groups.
MVEC Delaware E-L Stage 17 – 18 12 leaves separated; inflorescence well developed, single flowers separated to 14 leaves separated; flower caps still in place but cap colour fading from green.
MVEC Sunbelt E-L Stage 21 30% caps off.
MVEC Chambourcin E-L Stage 15 8 leaves separated, shoot elongating rapidly; single flowers in compact groups.
W Catawba E-L Stage 15 8 leaves separated, shoot elongating rapidly; single flowers in compact groups.
NWV Chardonel E-L Stage 15 8 leaves separated, shoot elongating rapidly; single flowers in compact groups.
R Seyval Blanc E-L Stage 17 – 18 12 leaves separated; inflorescence well developed, single flowers separated to 14 leaves separated; flower caps still in place but cap colour fading from green.
R Vidal Blanc E-L Stage 16 10 leaves separated.
R Catawba E-L Stage 17 12 leaves separated; inflorescence well developed, single flowers separated.
Vignoles E-L Stage 15 – 17 8 leaves separated, shoot elongating rapidly; single flowers in compact groups to 12 leaves separated; inflorescence well developed, single flowers separated.
F Chardonel E-L Stage 15 8 leaves separated, shoot elongating rapidly; single flowers in compact groups.
F Traminette E-L Stage 17 12 leaves separated; inflorescence well developed, single flowers separated.
F Cayuga White E-L Stage 15 8 leaves separated, shoot elongating rapidly; single flowers in compact groups.
D Concord E-L Stage 18 – 19 14 leaves separated; flower caps still in place but cap colour fading from green to About 16 leaves separated; beginning of flowering (first flower caps loosening.
D Vivant E-L Stage 16 – 17 10 leaves separated to 12 leaves separated; inflorescence well developed, single flowers separated.
D Mars E-L Stage 15 8 leaves separated, shoot elongating rapidly; single flowers in compact groups.