R. maximum has leaves thick and leathery, with still, turned-back margins, evergreen, oblong or broadly elliptical, glossy green (when old, rusty brown), 4 to 8 inches long, on hollow, flattened petioles. Calyx, 5-parted. Corolla, tubular. Stamens, 10. July.
A near relative to the azalea, with great, broad bunches of blossoms, white or pink, the petals spotted. Corolla 1 or 2 inches across. In cultivation the flower becomes very large, and is of white, yellow, pink, and red colors, one of the finest shrubs of our gardens. I have found its large, shiny leaves and showy blossoms wild on the borders of lakes in New Jersey. It is low and spreading, growing in clumps in moist, cold, shady places. In the Southern States, where it is more common, it attains a height of 20 to 25 feet. Stem grayish, and leaf-stalks yellow or yellowish green, covered with a hoary down. Common through the Alleghanies, from New York to Georgia; rare in New England.