Reed canary grass (Phalaris arundinacea) is a perennial non-native grass species that is aggressively invading mid-elevation meadows in Sequoia and Kings Canyon National Parks. It is considered native to some parts of California, but not to Sequoia and Kings Canyon National Parks. It is highly probable that these local populations are also hybridized with European strains of reed canary grass. Reed canary grass is a source of particular concern for park managers because it spreads rapidly, can alter stream and meadow hydrology, is very tenacious, and tends to exclude all other vegetation.

Identification

Reed canary grass is perennial and grows from tough rootstocks. It attains heights of up to 1.5 meters (5 feet), and produces cylindrical flower heads. These flower heads are 7 to 40 centimeters (2.8-16 inches) tall, and the flower clusters at the bottom of each head are often irregularly spaced. Reed canary grass is restricted to moist areas such as meadows and stream banks and is only known from middle elevations in Sequoia and Kings Canyon National Parks. These populations characteristically form dense stands, pushing out all other vegetation.

Look-Alikes

There are numerous grasses, sedges, and related plants that can appear similar to reed canary grass. The two most distinguishing features of reed canary grass are its cylindrical flower heads, and its habit of forming dense, exclusive colonies in mid-elevation wetlands.

Large photo: NPS by Athena Demetry; inset photo (modified): Wisconsin Department of Natural Resources

Reed canary grass excludes nearly all plant species in a mid-elevation meadow near Grant Grove in Kings Canyon National Park. Inset photo: mature flowering heads of reed canary grass.

Natural History

While reed canary grass is known to have fairly shallow roots, it grows extremely well on moist soils and soaks up large amounts of soil nutrients. It forms a thick, persistent thatch layer that prevents native plants from colonizing, even after the removal of standing plants. It can alter the water balance in wetlands by evaporating and transpiring large quantities of soil moisture and by clogging ditches and stream courses. Reed canary grass is capable of sprouting roots directly from its stems; this has implications for how the plant must be disposed of after it has been cut or uprooted (i.e. it cannot be mulched under).

Management

Reed canary grass is present only in moist meadows and riparian sites in Grant Grove. In 2002 park resource management personnel began removing small satellite populations. Ultimately the NPS intends to eradicate this species or contain it to the Wilsonia area. After attempting removal of this plant by hand, the park determined that hand digging is too disruptive to fragile meadow soils.

In 2002, the park began managing sites on meadow perimeters using a combination of hand removal and approved glyphosate herbicides. The stems were cut shortly before flowering and the grass was allowed to resprout. Three weeks after cutting, the resprouts were treated with herbicide. These targeted spot treatments treatment have been very successful, producing a 90% reduction in reed canary grass cover.

In 2006, when reed canary grass populations rebounded after several years of successful control, park staff determined that additional treatments and an aggressive, long-term commitment were necessary. We are now using repeat mowing, tarping (covering plants with black fabric for two growing seasons), foliar applications of glyphosate herbicide, and planting highly competitive native plants to shade out the reed canary grass.