There are several variety of gardens grass. One example of gardens grass is purple ornamental grass. Purple ornamental grass, also know as Pennisetum setaceum Rubrum, is annual plant that is used as a backdrop for other plants or as a focal point on its own. Purple ornamental grass also is referred to a red fountain grass from the reddish color of its blades. Feathery-like purplish blooms, with copper overtones that can reach up to 12 inches long, display from summer to fall on top of 3-foot hallow stems.