I am doing a cake for my husbands cousin's 16th birthday party, and she wants fresh roses cascading down the cake. The cake will be a 3 tier with rounds, 14, 10, and 6 each about 5 -7 inches tall... 

They are ordering the flowers as the same as the center pieces so I told them to let the flowrerist know and they would wrap them accordingly, but they need to know how many flowers... and I have no idea how many would I need... The picture of the flowers on the cake look like this but with thicker cake teirs... 

How many flowers do you think I need?