[Cal-IPC] Invasive rating: Phalaris aquatica (hardinggrass) is a perennial grass (family Poaceae) found throughout California. Hardinggrass is widespread in California because it has been used as a forage species and for revegetating after fires. 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). Hardinggrass is typically found along roadsides that are seldom mowed, allowing this tall, erect, leafy plant to dominate neighboring vegetation. In wildland habitats, hardinggrass can out-compete and displace native plant species. Tall stands of its dry foliage can present a fire hazard in summer. Cal-IPC Rating: Moderate (link added by Mary Ann Machi)

[Wikipedia] Europe & Caucasus native, Description, Geography: Phalaris aquatica, known by the common names bulbous canary-grass[2] and Harding grass, is a species of grass in the genus Phalaris of the family Poaceae. Description It is an erect, waist-high, stout perennial bunch grass, with grayish to bluish green leaves. Flowering heads are dense, spike-like, and usually 2 to 5 inches (50 to 125 mm) long. It is slow to develop from seed, but can form large bunches after several years.[3] Phalaris arundinacea (reed canary grass) differs from Harding grass in having more distinct rhizomes, and an inflorescence that is compact at first but becomes more open as the branches spread. Hybrids of Harding grass and reed canary grass have been produced. Varieties include 'AQ1', 'Uneta', and 'Australis'. P. aquatica is a quick-growing grass which incorporates and utilises soil nitrogen rapidly.[4] Geography Phalaris aquatica originated from Southern Europe and the Caucasus. It is naturalized in South Africa, Australia, New Zealand and the USA.[5] Although very recently introduced there, its pasture value was first recognised in Australia.[6] Domesticated cultivation then spread to the United States, Argentina and several other countries in South America, and New Zealand.[6] (link added by Mary Ann Machi)