Arundo donax

Description

Arundo donax (Giant Reed, Giant Grass, Giant Cane) is a large grass and grows from 10 to 30 feet tall. It grows in large clumps along lakes, rivers, streams and other wet areas. The plant looks like bamboo and is often mistaken for such. Arundo spreads by sending out runners from the main plant. These runners, which are called rhizomes, can float downstream and establish new infestations.

Problems with Arundo

Arundo displaces native riparian plants and wildlife due to the large, dense stands it forms. Arundo grows vertically without any horizontal branching and does not provide shading to the in-stream habitat, which can lead to increased water temperatures and reduced habitat quality for fish and other aquatic wildlife. Arundo provides limited food and habitat for native wildlife and can be found devoid of wildlife including insects, birds, and mammals.

The dense stands of Arundo can increase erosion problems along levees and canals. Arundo uses up to 3 times as much water as native riparian plants, thus altering water quality and availability in some areas. The dense stands of Arundo provide an available fuel source for fires, increasing the hazard of wild fires. During floods, Arundo can also create a hazard when trapped behind a bridge or other structure.

Where is Arundo in the Parkway?

Arundo is found growing in creek beds that flow into Millerton Lake and downstream on the San Joaquin River throughout most of the Parkway. Some notable infestations include land around the California Department of Fish and Game fish hatchery, Jensen River Ranch, around the gravel mining operations downstream of Hwy 41 and in the Milburn Unit of the San Joaquin River Ecological Reserve. In addition, many smaller clumps of Arundo are common along the Parkway.

What are we doing about Arundo?

We have worked with the California Conservation Corps to remove a large infestation at Jensen River Ranch. Removal techniques include manual chopping, pulling and digging out the root mass, and using a tarp to prevent access to sunlight and further plant growth. The use of tarps in this area has been successful. Staff and volunteers periodically recheck the area and remove any new shoots. Arundo can lie dormant for three or more years, so periodic maintenance is necessary to prevent re-establishment. Manual and mechanical control of Arundo should be done when the plant is dormant, from October to March.

Staff and volunteers also tackle patches of Arundo during workdays.

For more information about Arundo, check out the article "Required Weeding" from the Fall 2001 edition of the Parkway Current, the River Parkway Trust's quarterly newsletter.