Arundo donax

Giant reed

Family: Poaceae · Type: perennial · Not Native

Conservation status: Cal-IPC Yes

Giant reed is a naturalized perennial grass found in northern California Coast, Klamath Ranges, central Sierra Nevada Forest, Central Valley, Central Coast, southern coastal regions, southern California, San Gabriel Mountains, and desert areas in moist places, seeps, and ditchbanks at elevations below 1,500 meters. Flowering from March to September, this robust grass produces silvery to brownish-purple flowers in dense, ascending plume-like clusters up to 70 centimeters long. Growing to impressive heights of 2 to 10 meters with thick, woody stems and smooth nodes, it forms dense, towering stands in wet environments. Its elongated leaves are broad, measuring 2 to 6 centimeters wide and up to 1 meter in length, creating a dense, dramatic green backdrop. The plant's intricate flower clusters feature thin, silvery spikelets with silky-haired lemmas, contributing to its distinctive and dramatic appearance.

Habitat: Moist places, seeps, ditchbanks

Bloom period: Mar-Sep

Elevation: < 1500 m

Bioregions: NCo, KR, c SNF, GV, CCo, SCoR, SCo, SnGb, D

California counties: Kings, Orange, Riverside, San Bernardino, San Diego, Ventura, Kern, Los Angeles, Madera, San Mateo, Santa Barbara, Sonoma, Solano, Santa Clara, Lake, Contra Costa, Fresno, Marin, Monterey, Sacramento, Napa, Imperial, Inyo, Glenn, Butte, Stanislaus, Mariposa, Humboldt, Yolo, Tehama, Shasta, Mendocino, San Luis Obispo, Merced, San Joaquin, Amador, Colusa, San Benito, Placer

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Jepson eFlora, Cal-IPC, and more.