Costmary is a perennial herb sometimes called mint geranium. But costmary is neither mint nor a geranium though its leaves have a spearmint flavor. Costmary makes an attractive, fragrant hedge in the herb garden or perennial border. Its leaves can be used fresh or dried to flavor green and fruit salads and make tea
Plant costmary in loamy, humus-rich soil. No additional fertilizer is needed. Add aged compost to the planting bed ahead of planting.
Costmary can look leggy if not clipped back. : For more foliage, discourage flowering. When plant flowers, cut costmary back to 3 or 4 inches above the soil; it will fill back out in a few weeks. Divide plants every 3 years.