Varieties of Horse Mint

General Cultivation

• Horse mint is hardy to U.S. Department of Agriculture plant hardiness zones 3 through 9 and thrives in full sun to partial shade and moist, well-drained soil, although a few varieties are drought tolerant. Because plants grow on underground runners, they readily naturalize in open areas and even faster in shade. On average, horse mint plants reach a height of 2 to 4 feet, making them suitable as background border plants. Horse mint reliably returns each season, but cultivars perform better if divided every few years. This will also help improve air circulation between plants and deter mildew diseases. Removing spent flowers will promote more blooms through summer into the fall.

Oswego Tea

• Oswego tea (Monarda didyma) is so-named because early settlers in Oswego, New York, made tea from the leaves of the plant when black tea (Camellia sinensis) became scarce. Also known as scarlet bee balm and red bergamot, this variety of horse mint features bright red flowers and mildly mint-scented leaves. This is the species most commonly offered for sale in garden centers and from which many cultivars have been developed. Oswego tea occurs naturally and is grown as a garden ornamental throughout USDA zones 4 through 9.

Wild Bergamot

• The green-grey leaves of wild bergamot (Monarda fistulosa) are hairier than Oswego tea leaves and not as toothed, but the leaves that cup the flower heads display a slightly pink tone. In further contrast, the flowers of wild bergamot are a soft lavender color and the leaves impart a flavor and aroma reminiscent of mint combined with oregano. This species is also hardy to USDA zones 3 through 9, but can withstand drought, heavy clay and rocky soil.

Cultivars

• Numerous cultivars of horse mint have been produced, many by crossing Oswego tea and wild bergamot. Among the red varieties are "Raspberry Wine," "Cambridge Scarlet" and "Colrain Red,” the latter two of which demonstrate exceptional resistance to powdery mildew. "Donnerwolke," "Mohawk" and "Sagittarius" feature lilac-colored blooms, while "Purple Crown" and "Violet Queen" represent deep purple varieties. The dwarf varieties "Petite Delight" and "Pink Supreme" produce pink blossoms and only reach up to 16 inches in height. Although these cultivars are hardy to USDA zones 3 through 9, USDA zones 4 through 8 are recommended for "Pink Supreme.”