Cortaderia selloana is a perennial in the grass family (Poaceae) growing 6-13 ft. (1.8-4 m) in height. Lateral roots can spread to 13 ft. (4 m) in diameter and 11.5 ft. (3.5 m) in depth.
Foliage
Cortaderia selloana leaf blades can get up to 6 ft. (1.8 m) long and 1-3 in. (2.5-7.6 cm) wide. They are V-shaped in cross-section, and bluish green in color. The upper surface is smooth at base. The lower surface may be smooth or hairy towards collar. Leaf tips are bristly and curled and margins are rough and sharp.
Flowers
The inflorescence is a showy dense, feathery, 1-4 ft. (0.3-0.9 m), stiff, light violet to silvery white panicle.
Fruit
The wind-dispersed seeds of Cortaderia selloana can be found at distances up to 20 mi. (32.2 km) away from the parent plant. Each female flower head can produce up to 100,000 seeds.
Ecological Threat
Cortaderia selloana requires sandy soils, ample moisture, and sunny locations. It tolerates warm summer temperatures, intense sunlight, and moderate drought. The vigorous growth habit and large size enables it to invade natural ecosystems. Cortaderia selloana can invade sandy, moist ditch banks. Vegetative reproduction can occur when root fragments develop shoots at the base of the plant. It has the ability to form dense stands where it can quickly become a fire hazard.