Giant reed

Common Name(s)

Giant reed

Giant cane

Elephant grass

Carrizo

Arundo

Spanish cane

Colorado river reed

Wild cane

Scientific Name

Arundo donax

Family

Grass family (Poaceae)

Reasons for concern

Giant reed creates a tough root base that uproots native plant and outcompetes them for necessary resources like water and nutrients, decreasing natural biodiversity. These plants also disrupt the natural floodplain by blocking river flow and overall, use significantly more water than native plants. Giant reed also provides large amounts of dry biomass that feeds fires.

Classification

Class B Noxious Weed, categorized as a species of plant that is known to occur, but of limited distribution in the State and may be a high priority pest for quarantine, control or mitigation if a significant threat to a crop, commodity, or habitat is known to exist.

Botanical description

Tall, bamboo like grass with long, alternating leaves

Leaves

Rounded at the base and taper at the tip, alternating leaves 1 to 2 inches wide and 1 to 2 feet long, Lower part of the leaf is yellow, has fine hairs, and clasps the stem in a distinctive “S” wave. The rest of the leaf is pale green to blue green, but rarely can be variegated

Stem(s)

Robust, hollow, almost woody 6-16 feet tall, up to 2 inches in diameter with knotty nodes

Inflorescence

Dense plume, 1 to 2 feet long, white to brown depending on maturity

Roots

Tough, fibrous, lateral rhizomes, and deep tap roots.

Native to

Asia

Where it grows

Riparian environments, long disturbed and undisturbed streambanks, desert springs, flood plains, drainages, and irrigation waterways, or anywhere water collects

Lifecycle

Perennial

Reproduction

Direct from stem and rhizome pieces

Weedy Characteristics

Giant reed can grow from rhizome fragments as small as 1 inch, and grows quickly.

Control Strategies

Repeat applications of glyphosate are effective when applied after the flowering season. When manually removing the plants, make sure to get the entirety of the rhizomes and dispose of them properly, as even a small piece of rhizome can grow into another plant. To ease removal, cut the above ground canopy with a mower or shears, then remove the roots and rhizomes with a shovel or by hand

Gallery

References