Other Common Names: Italian sugarcane, plume grass, giant cane, hardy pampas grass
Weed class: B
Year Listed: 2015 as a Class A; changed to Class B in 2017
Native to: North Africa, Asia and Europe
Is this Weed Toxic?:
not known to be
Why Is It a Noxious Weed?
Ravenna grass is a large, nonnative, perennial, ornamental grass that has been recently been found escaping in eastern Washington. It has large basal clumps of leaves that can crowd out native and desirable plant species. In Washington, seeds of Ravenna grass are spreading from ornamental plantings and can successfully germinate in a wide range of habitats, including locations near the Columbia and Yakima Rivers.
How would I identify it?
Ravenna grass is a tall, perennial grass that forms clumps of basal leaves called tussocks. Flowering stems are erect and up to 13 feet (4 meters) tall. Leaves occur on stems up to the base of the inflorescences. Stems can be reddish or other colors as flowers mature. Inflorescences are at stem tips and are slender and silvery in color.
Inflorescences occur at stem tips and are plume-like, dense panicles, 9.8 inches to 2 feet (25 to 60 cm) long by 4 to 6 inches (10 to 15 cm) wide. Primary panicle branches are 2.4 to 7.9 inches (6 to 20 cm) and are appressed or spreading.
Spikelets have 2 florets, and are 3 to 7 mm long and purplish. Spikelets have silky hairs and occur in
unequal pairs, where the lower spikelet is sessile and the upper spikelet is stalked.
Its basal leaves are long and narrow, 3 to 4 feet long by 0.5 to 1 inch wide. Basal clumps of leaves can be 4 to 5 feet across. Leaves are medium gray-green and have a white midvein. The upper side at the base of the blade is densely covered with long, fuzzy tawny (tan-yellowish) hairs that typically hide the ligule and upper blade base surface. Leaves on the flowering stems are shorter and occur all the way up the stems to the base of the inflorescence.
Stems, called culms, are stiff and grow 5 to 13 feet tall and around 0.4 inches (1 cm) in diameter. Lower stem nodes have yellowish hairs and upper nodes are glabrous below the inflorescence. Stems, especially large stems, can turn red when in flower. Old flowering stems may remain for one year or longer.
Fruit Seed Description
Ravenna grass has tiny seeds that are dispersed by wind and water.
May Be Confused With
Where does it grow?
Ravenna grass grows in moist places such as ditches, marshes, wetlands, and riparian areas. It tolerates a wide range of conditions. In California, it was noted to be growing in much of the same type of habitat as common reed, Arundo donax, and saltcedar, Tamarix parviflora. Please click here to see a county level distribution map of Ravenna grass in Washington.
How Does it Reproduce?
Plants can reproduce by seed and can also be propagated by plant division in early summer as it begins to emerge. Plants may not bloom in colder climates, but they do reseed themselves copiously in warmer climates
How Do I Control It?
Though Ravenna grass leaf margins are not as sharply serrated as Cortaderia species, its hairs can be mildly irritating, and it is still important to protect yourself by wearing gloves when handling the plants. Once plants are controlled, plant or seed bare ground with native or non-invasive, non-native plants to provide competition. Instead of planting Ravenna grass in ornamental plantings, use non-invasive alternatives.
Plants can be dug out of the ground, but it is important to remove the roots to prevent resprouting. Plants will resprout after burning, cutting or grazing, so follow-up control will be needed if the roots are not removed. If it isn’t possible to remove all plants before seeds develop, consistently removing plumes before seeds mature will help to prevent population expansion. However, plants that have had plumes removed may develop more plumes during the flowering season, so follow-up plume-removal may be needed. Bag and remove plumes to prevent seed developing on site.
Planting or seeding desirable, non-invasive plants can provide competition to reduce germination and seedling establishment.
There are no approved biological control agents for Ravenna grass.
Currently, herbicide treatment information on Ravenna grass is not available in the PNW Weed Management Handbook, but check back as information is continually updated. Herbicide control efforts of Ravenna grass commonly consist of spot treatments of glyphosate applied to plants that are fully mature, but before flowers produce viable seed. This likely occurs during the early summer months. Contact your county noxious weed coordinator for more information.
For More Information
See our Written Findings for Ravenna grass Saccharum ravennae
Franklin County NWCB Fact Sheet on Ravenna grass