For use directly on cakes, use a holly leaf cutter with dark green gumpaste and red gumpaste for the berries. You can obviously use other colors to match a color theme, too.
For the berries, just roll out tiny berries and press a small dot in them. You could put a black food coloring dot on them when they dry if you want to poke a hole in them.
Let the berries dry on a foam surface that won't make them flatten out.
Roll the green gumpaste out using a pasta roller and cut the leaves out. This plunger cutter has a veiner attached so I veined them using the plunger.
When you cut the leaves and they're veined (use a basic leaf veiner if you don't have the plunger cutter set) take a butter knife or the edge of a spatula and gently press the center vein of the leaf. Bend the sides of the leaves up to give them some motion.
Dry the leaves on any surface that will let them dry slightly folded.
When they're all dry, arrange them on the cake or cupcakes in clusters or overlap them to make a wreath. If you want them to be shiny, brush them with confectioners glaze or a corn syrup/vodka glaze and let them dry before using them on the cake.
To lay them out in a wreath configuration, strt with the outer row first, then add another layer of leaves overlapping that one. Keep going until the wreath is as full as you want it to be.