Choose a full rosebush with a healthy center cane or stalk. Floribunda varieties provide large, showy flowers that are perfect for a topiary. Place a metal or wooden stake near the center stalk to support and strengthen the plant as it grows.
Prune away all other canes, except the one you have selected, and cut them down to ground level with pruning shears.
Place a wire topiary frame at the top of the rosebush. Weave the bush's branches in and out of the shape to cover the wire. Cut three to four pieces of floral wire to about 4 inches in length. Tie the wire loosely to the branches to hold them in place on the frame.
Cut away any branches that are misshapen or have obvious insect damage. Make lateral cuts at a 45-degree angle just above the bud.
Shape the rosebush once during the summer and fall growth periods; never prune in the winter. Remove the floral wire pieces once the rose topiary takes shape.