36701

This is a table of how I worked it out
Week flowers
week 1: 2
week 2: 4
week 3: 8
week 4: 16
week 5: 32
week 6: 64

The amount of the flowers doubles every week so if the stem splits into 2 branches in the 1st week then it doubles.In the 2nd to make 4 branches then it doubles again and again until it gets to the 6th week and it has 64 branches and every branch grows a flower so there would be 64 flowers