Cut approximately six green or red apples in half lengthwise using a paring knife. Have more apples on hand in case you need them to fill the vase.
Slice a lemon in half and squeeze the juice over the cut portions of the apples to prevent them from turning brown.
Cut an 8-inch-by-8-inch block of floral foam and soak it in cool water. Place the foam in the center of the bottom of a 22-inch clear glass cylinder vase.
Trim the stems of five or six fresh orange, red and yellow roses one or two inches taller than the vase. Cut the stems at angles to encourage maximum water absorption. Insert the stems into the foam, staggering the colors for a varied look.
Insert the halved apples into the vase, completely surrounding the foam to conceal it. Fill half or three-fourths of the vase with the apple slices, depending on your preference.