• Giant Sequoia Trees

    Sequoia & Kings Canyon

    National Parks California

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  • Sequoia and Kings Canyon National Parks Institute Stage 2 Fire Restrictions

    Effective July 28, 2014, the parks are in Stage 2 fire restrictions. See link below for more information. These restrictions will remain in place until further notice. More »

  • Road Construction Delays on Park Roads for 2014 Season

    Expect occasional 15-minute to 1-hour delays in Sequoia and Kings Canyon National Parks on weekdays only (times vary), including delays to/from the General Sherman Tree, Crystal Cave, and Grant Grove. More »

  • Vehicle Length Limits in Sequoia National Park (if Entering/Exiting Hwy 198)

    Planning to see the "Big Trees" in Sequoia National Park? If you enter/exit via Hwy. 198, and your vehicle is longer than 22 feet (combined length), please pay close attention to vehicle length advisories for your safety and the safety of others. More »

  • You May Have Trouble Calling Us

    We are experiencing technical problems receiving incoming phone calls. We apologize for the inconvenience. Please send us an email to SEKI_Interpretation@nps.gov or check the "More" link for trip-planning information. More »

Giant Reed


Giant reed (Arundo donax), also known as arundo, is an aggressive invader of riparian areas, ditches and other wet sites throughout California. It is not well established in Sequoia and Kings Canyon National Parks, but it is a species of special concern. Giant reed seems to have originated in Asia and has spread to southern Europe, the Middle East, Australia, and the Americas. It is considered to be well adapted to extreme fire events, and in fact it seems to promote fire. Arundo has the alarming tendency to displace nearly all native species from the areas which it invades. It is known to take over large portions of low-elevation stream beds and to form dense, very persistent thickets.

Giant Reed plants, topped by tall purplish flower clusters, tower over a riparian area.

Giant reed can grow up to eight meters (25 feet) in height.

Photo by Brother Alfred Brousseau, St. Mary's College


Giant reed is a bamboo-like perennial grass that can grow up to eight meters (25 feet) in height. It has thick creeping rootstocks. The stems are hollow and can reach 4 centimeters (1.6 inches) in diameter. The flower clusters are plume-like, often purplish in color, and can reach 60 centimeters (2 feet) in height. Arundo turns mostly brown in the wintertime, and grows most vigorously in late spring and early summer. Aside from cultivated bamboo, there are no grasses in California that could be mistaken for giant reed.

Natural History

Giant reed requires a tremendous amount of water to persist. This, coupled with its ability to quickly dominate entire stream channels, makes arundo a particularly pernicious weed in the thirsty state of California. Little is known about arundo's reproductive ability in California. There are no observations of the plant sexually reproducing in this state; it appears to spread to new locations via fragments of stems and rootstocks, especially during flood events.


There are a few small populations known to be in Sequoia National Park. All are in and around the Ash Mountain area. Natural Resource Management Personnel began eradication of this species in 2002.

Did You Know?

Sequoia fire scar.

The large black areas at the base of many sequoia trees are fire scars. Even though fire may eat into the very heart of a sequoia tree, the tree can survive so long as the fire doesn't kill the living tissue all the way around the tree. Over time, the fire scars gradually heal over and disappear.