Flower dupe glitch

Found a glitch that can dupe flowers
place flower on the floor
place block of sand / gravel / anvil on top
break the block the flower is on
get 2 flowers instead of 1

video of this in action:
https://www.youtube.com/watch?v=HrtpC694Fuk&feature=youtu.be
sorry it got cut off I don't know why but it doesn't really matter anyway.