Source: Martha Stewart
Traditionally, topiaries are made from plants like ivy, boxwood, and myrtle, but they can be created from just about any woody perennial. Potted rosemary trimmed into a topiary sphere or an elongated pyramid looks elegant in the garden and provides herbs for the kitchen. And while training rosemary takes several years, many beautiful trained plants are available from nurseries.
To care for your rosemary, a shrubby herb, plant it in a soil mix consisting of two parts potting soil, two parts peat, one part sand, and one part compost. Allow the top inch of soil to dry out between waterings, but mist its leaves regularly. A Mediterranean native hardy in Zones 8–10, the plant prefers a sunny location and dislikes extreme cold, so if you garden in a colder climate, move your rosemary to a cool, sunny spot indoors when the temperature falls below freezing, being careful not to overwater.
To attain a full, bushy topiary, prune the plant constantly. The more you trim the new growth, the more the tips will branch out, and you can use the trimmings in all your favorite recipes calling for fresh rosemary.