Genus Mulenbergia Species capillaris Cultivar Common Name Muhly Grass Patent ID Height 2 to 3 Feet Spread 2 to 3 Feet Habit Clumping grass. Moderate to fast growth rate. Zone 6 to 10 Culture Full Sun. Flower Plumes in fall, look like a purple cloud from far away. Flower Color Purple. Foliage Blue/green needle like. Deciduous. Category: Grass Description Absolutely one of the most beautiful ornamental grasses around.