I adore peonies.  The large, soft puffy blossoms are one of my favorite flowers to make from sugar paste.  They do take a while to make, building up all those layers, but the final result is so worth it.   Because they are a larger flower, they can make a very dramatic statement on  a wedding cake.   With a simple white background,  this elegant, extravagant drape stands out.   Used with a color background, and a bit of modern design touches and the cake has an entirely different feel.   Which direction would you go?