Della Robbia Tutorial by Polly Morris: Trees are made with plastic Christmas foliage and bottle brush trees. Wash foliage with detergent and dry. Spray with dark green Design Master floral spray-- that stuff sticks to anything and eliminates the tell-tale plastic shine. Snip foliage into a variety of sizes as needed. I used a mini glue gun to adhere plastic foliage to tree. I built wreaths on cardboard bases painted to match foliage. The frost is grated Styrofoam glued on with matte medium.