Reed canary grass, or Phalaris arundinacea, a perennial plant that occurs throughout much of the world except for Antarctica and Greenland, flourishes in moist soil, although it can survive drought conditions. Despite its use by humans as a forage crop for livestock, reed canary grass grows aggressively, and many locations have listed it as a noxious weed because it threatens delicate and valuable ecosystems like natural wetlands.
Reed canary grass is thought to be native to North America; however, Europeans have been using it as forage crops to feed livestock, and differences between the European and American grasses are difficult to detect. The plants can survive in temperatures as low as -3.33 degrees C (-38 degrees F), yet cannot tolerate heat. Therefore, it grows throughout much of the world except for polar regions and the hotter climates.
Reed canary grass, a coarse green grass, grows to about 1.5 m (5 feet) tall, and clusters of yellow flowers bloom from May to either June or August, depending on the climate. It reproduces by small, black seeds or by spread of rhizomes, which are small, root-like structures in the soil. The plants form dense areas of growth where they prevent other plants from becoming established, and they spread outwards radially, or in a widening circle.
People have used reed canary grass as a cheap, plentiful forage crop for livestock because it grows quickly and easily in both moist and dry soils and in cold or temperate climates. For the same reasons, it has also been used to prevent erosion in areas where fast-growing plants are needed. More recently, treatment wetlands, which filter sewage, have used reed canary grass to remove contaminants from waste water by drawing them out of wetlands soils.
Reed canary grass has been classified as a noxious weed because it threatens natural ecosystems such as marshes and other wetlands. Once a growth becomes established, this hardy and aggressive plant soon replaces native species, which cannot compete with its rapid growth. As the canary grass spreads, it overwhelms more species, resulting in a loss of diversity. Over time, a monoculture emerges where nothing but reed canary grass grows, and removing it has proved difficult because it is such an effective competitor.
Removal of reed canary grass has caused headaches for scientists because it often grows in valuable wetlands. Grazing animals cannot reach the grass in a marsh, nor can heavy equipment be used. Even if mowers remove the plants, the rhizomes, or root-like structures, remaining in the soil quickly regrow. In addition, herbicides kill most plants because they are not selective enough to eliminate only the reed canary grass. An effective way to reduce this invasive species is burning the plants: over time, repeated burnings reduce the incidence of regrowth.