Pampas grass (Cortaderia selloana) is a large perennial grass native to Brazil, Argentina and Chile. It grows in large clumps eight to 10 feet high, in late summer bearing silvery-white or pinkish silken plumes that rise to a height of 12 feet.
The plume-like inflorescence differs between male and female plants. Female plants produce plumes that are broad and full due to silky hairs covering the tiny flowers. Male plumes appear narrow and thin because of the absence of hair on the flowers. However, the difference in appearance is not so obvious at first glance.
There is also considerable variation among seedlings in growth habit, period of flowering, and size and shape of plumes. Therefore, if uniformity is desired, pampas grass should be propagated by dividing the clump rather than by seed.
Pampas grass can be a very attractive and functional plant when used correctly in the landscape. It can be used as a specimen plant in isolated locations on large lawns. Because it grows very rapidly into a massive plant, pampas grass is an excellent screening plant for sunny locations.
Unfortunately, pampas grass is often used as a foundation plant. It is often purchased from a nursery as a small plant and planted very near the home. The plant will look great the first year. But after several years, it grows so large that it becomes difficult to find the house for the pampas grass.
In selecting sites for pampas grass, regard should be paid to the danger of damage to passersby from contact with the very sharp saw-like edges of the leaves.
Pampas grass should be planted where it will receive full sun most of the day. When grown in shady areas, it will grow very slowly and usually will not produce plumes.
The plumes of pampas grass are highly prized for indoor decorations. Plumes used for this purpose should be cut as soon as they have fully emerged. They can be used in dried arrangements immediately after harvesting or dried by hanging upside down and used later. If mature plumes are brought indoors, they will fill the home with delicate fluffy flowers, which can be a bigger problem than a shedding dog or cat. This shedding can be prevented by spraying mature plumes with hair spray.
Once established, pampas grass is practically trouble-free. There is no need to spray for insects or any other garden pest. It will grow in most soils and responds favorably to frequent fertilization. To obtain good growth and plume production, pampas grass should be fertilized with a complete fertilizer (10-10-10) at a rate of two pounds per 100 square feet four times each year.
Before growth begins in the spring, prune away any brown leaves and dead materials that accumulate at the base of plants.
It is advisable to move slowly and wear jeans, a long sleeve shirt, and gloves when pruning pampas grass. The sharp leaf blades will cut through the skin of hands, arms, legs and other unprotected parts of the body. If winter is particularly harsh and a great deal of browning has occurred, the entire plant can be rejuvenated by cutting it back to within two feet of ground level with lopping shears or chain saw.
Striking feathery plumes combined with large, graceful clumps of foliage make pampas grass a very interesting addition to most landscapes.