That is more than one flower.
The circle on the top tier is a regular gumpaste peony and you can google many websites that have a demo.
Each of the petals for this entire "thing" needs to be wired individually so that you can bend them to the nice shape after sticking the "thing" onto the cake.
The drape below the flower is separate piece made from larger petals and wired into that wedge shape. Make this smaller than the picture shows, so that it fits onto the second tier.
This wedge is attached to the cake first, then the gumpaste flower is added above it at the right angle.
I'm liking this cake also--what size to you think the tiers are in relation to the size of the flower??
Looks to me like the diameter of the flower is same as the second tier. The extra wedge is the same width but longer--looks like 1.5 times one tier's height.
I would make this by eyeballing the flower to the cake pan that will be used for your actual cake. Make a bunch of extra petals in the largest flower size, and wire them according to the size that you need.
But for a two tier cake, the flower would have to go on the top so that there is room along the sides for the wedge to drape down as this picture shows.
Thank you so much!!!! that was extremely helpful... I think due to her just wanting two tiers I may ask her if she will mind not having the petals draping down and just do the large peony. She doesnt want anything on the very top of the cake!
You can stick the peony onto the edge of the top tier, so that it all drapes below the top edge. That leaves the top flat for whatever else she wants, and it makes the side of the cake look very much like the picture.