The official website of the Elkhorn Slough Foundation and Elkhorn Slough National Estuarine Research Reserve
Elkhorn Slough Plants: Harding Grass

Scientific Name:
Phalaris aquatica

(Grass family)

Found at the Slough:
Grasslands, grazing or grazed areas, roadsides.

Did you know...
Harding Grass poses a fire hazard in dry summers and is then used to re-vegetate areas after wildfires.

Harding Grass or Bulbuous Canary Grass is a non-native, moderately invasive, perennial grazing grass. It is also known as Phalaris aquatica or Phalaris stenoptera, P. tuberosa var. stenoptera. It is commonly seen at the Reserve, especially in the grasslands near the Visitor Center and at the Porter Ranch property.

It is most common in coastal valley and foothill grasslands from Oregon to the Mexican border. It is also found in the Sacramento and San Joaquin valleys at elevations below 4,000 feet (1,200 m). Harding grass is typically found along roadsides that are seldom mowed, allowing this tall, erect, leafy plant to dominate neighboring vegetation. In wild land habitats, Harding grass can out-compete and displace native plant species.

Harding Grass
Harding Grass

Harding grass is probably a native of the Mediterranean region of Europe and was originally introduced to North America as a forage plant from Australia (Crampton 1974). It is now more or less naturalized at lower elevations in California. Harding grass is commonly seeded as a forage grass on valley and foothill rangelands in California. It is used in seeding prepared land in oak woodlands of the foothills as well as cleared brush lands. Because of its wide use as a forage plant, it has spread throughout most of the San Joaquin Valley and adjacent grasslands, as well as portions of northern and southern California.

P. aquatica has the potential to establish in dense stands, at least in localized areas. It can displace native species particularly in preserves with grassland or some grass species. Areas that should be closely monitored are those that are adjacent to private grazed lands or weedy areas that contain Harding grass. Grazed lands with established Harding grass populations provide a source of seed that may disperse to adjacent areas and are, therefore, a constant threat to native habitats.

Further reading:
Weed Control by Species Handbook - contains information on the biology and control of over 50 non-native plant species in the region, including Harding Grass.

Outside links / sources:


Header photo by Sarah Danenhauer

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This site is maintained by the Elkhorn Slough Foundation in partnership with the Elkhorn Slough National Estuarine Research Reserve