Beginner caketeer here, just wondering is there any way to get the back of leaves & petals smother when using wires for a floral display on cakes?

If you let the center of the 'dough' thicker you can stick the wire into it. Roll out the fondant/gp  leaving a line in the center where the fondant is a bit thicker.  ONce the leaf is cut, you roll from the center to the edge a bit to thin it, leaving a thicker center.  Hope that makes sense.  This way the back is as smooth as the from (except for viens.)

Yes, that does makes sense.  Thank you I will give it a try.