Pennisetum setaceum is a a species of large bunch grass that belongs to the Poaceae family. Commonly known as fountain grass, Pennisetum setaceum is native to tropical regions of Africa and southwestern Asia. Pennisetum setaceum is a perennial in its natural climate and an annual in cooler regions. Fountain grass is named after the visual effect of the smooth swooping foliage resembling the shape and movement of a flowing fountain.
Fountain grass is a clump-forming ornamental grass that produces tall, narrow foliage from a rhizome or stolon. A rhizome is a central rootstock that sends out a plant's roots and foliage. A stolon is a stem that branches out along or beneath the ground to create new growth. Fountain grass foliage grows 3 to 5 feet (about 1 to 1.5 meters) tall in bunches that are 2 to 3 feet (about 60 to 90 centimeters) wide. During the spring and early summer, fountain grass produces feathery spikes of purple or pink flower heads. These flowers fruit into a light brown grain in the autumn.
There are a handful of popular cultivars of the Pennisetum setaceum, including "Burgundy Giant," "Atrosanguineum" and "Cupreum." P. setaceum "Burgundy Giant" has dark burgundy leaves that are about 1 inch (25 millimeters) wide and flower stalks with light pink flowers that are 4 feet (about 1.2 meters) long. The dramatically colored P. setaceum "Atrosanuineum" is the same size and has rich purple flowers with deep burgundy foliage. P. setaceum "Cupreum" has narrow foliage that is brilliant green in warm climates and varying shades of red in northern regions.
Pennisetum setaceum can be propagated in the spring by seed or by dividing established plants. Fountain grass should be planted in areas that offer abundant direct light with little to no shade. New plants will establish themselves quickly if they are planted in fertile soil with good drainage. This species prefers a hardiness zone of 9 or 10. As long as it is properly maintained, Pennisetum setaceum can be planted as an accent plant, ground cover or as general purpose landscape plant.
Some cultivars of fountain grass are capable of propagating prodigiously in certain conditions and are considered invasive plants. Pennisetum setaceum is listed as an invasive species in many states and can take over an area if not managed properly. The most common cultivars like those discussed above do not spread very quickly. Other cultivars like "National Arboretum" and "Moudry" are more difficult to control.