Perennial of the Lamiaceae family, this cultivar is derived from Monarda didyma, a species native to the eastern United States, where it naturally grows at the edge of moist forests and along streams. 'Cambridge Scarlet' is one of the oldest and most well-known cultivars, obtained in the early 20th century.
It forms large, vigorous, upright clumps, reaching 80 to 100 cm in height. The stems are square, characteristic of the family. The leaves are oval, slightly toothed, medium green, aromatic when crushed — their scent evokes lemon thyme, which gives the species its common English name of bergamot.
The flowers, gathered in very characteristic terminal whorls, are tubular, slender, of an intense scarlet red, borne on dark purple bracts that enhance the color contrast. The flowering extends from July to August in cultivation under our latitudes.
It requires fresh, deep, and well-drained soil, in full sun to partial shade. Summer drought promotes powdery mildew, the main flaw of this cultivar. Regular division every two to three years maintains the vigor of the clump.