Most rosemary (Rosmarinus officinalis) cultivars are fully hardy only to Zone 7, but several, including 'Madalene Hill', 'Arp', and 'Athens Blue Spire' are slightly hardier than most. If you find the right microclimate for them in your yard, you may succeed with them. A microclimate is a pocket in your yard that differs from the basic growing conditions in your area. Because rosemary thrives in full sun and well-drained soil in a protected location, those conditions are what you should try to duplicate. Perhaps a raised bed on the south side of your home would provide a little extra warmth over the winter as well as permit the plant to get full sun. You could also grow rosemary in a container and move it indoors over the winter.