Usually floral topiary plants and bushes are "standards:" a round sphere covered with flowers sitting on a straight trunk. Floral designers use centerpieces of flowers arranged to look like topiaries. Holiday topiaries combine potted bushes with fresh cut flowers. Becke Davis in "At Home in the Garden," suggests adding topiaries to bring a sense of novelty to a landscape.
Any plant that flowers profusely and has a straight strong stem can be trained into a topiary. The plant is shaped into a topiary by removing the branches from the lower stem or trunk and pruning the top into a round spherical shape. Topiaries do come in other shapes of double and triple spheres, spirals, cones and animal shapes. Animal shapes are pruned free-form or use wired forms as the basis for the plant to grow up and around. Roses, hibiscus and lantana are three flowers easily trained as standard topiaries. Flowering vines are used to train using the metal wire forms.
Floral designers mimic the shape of a standard topiary in two ways. The designer cuts a ball from floral foam and secures it to a straight trunk that's held firmly in a pot. She then covers the ball with medium-sized flowers such as button mums, carnations or marguerite daisies, placing the flowers as close together as possible. The stems of the flowers are cut to 2 inches and poked into the foam.
As an alternative, the florist selects large size flowers such as roses and wraps the stems together about 2 inches below the flower heads and again about 6 inches down the stem. He cuts the stems to all the same length and places them in a vase that is barely wide enough to hold them. The flowers open into a rounded shape. Sunflowers make an unusual topiary shape.
Decorate rosemary bushes in a cone shape resembling a Christmas tree or a standard. The leaves of rosemary are thin but abundant on the plant. They easily hold flowers. Cut fresh baby's breath into small bunches and stick the bunches deep into the rosemary so only the flowers show. The baby's breath will dry in place. Sweetheart rose buds will work and dry in place as well. If you want to keep the flowers fresh, place the stems into a floral pick containing water before putting it into the rosemary. Floral picks are about 3 inches long so a larger rosemary topiary is required.