Phragmites, (Phragmites australis), also known as common reed, is a perennial grass and is thought to be one of the most widespread plants on Earth. It is believed to have originated from the Middle East. Genetic research suggests that there are three separate lineages of Phragmites sustralis in North America: one lineage is widespread and native to North America (Phragmites australis ssp.); one is found in North and South America (Phragmites australis subsp. Also referred to as the “Gulf Coast” linage); the third lineage is introduced and invasive (Phragmites australis). Phragmites spreads by seed and rhizomes and is easily disbursed by natural means as well as by human activities; Phragmites plants have the ability to produce hundreds to thousands of seeds per year.
Introduced Phragmites outgrows and out-competes native vegetation; it rapidly creates dense patches that quickly reduce biodiversity within an ecosystem. It alters the hydrology of wetland regions, and also increases the potential for natural fires to occur. Due to the ability of Phragmites to choke out native vegetation, it can negatively impact the overall health of species which relay on wetland ecosystems for survival.
Phragmites grows in dense stands in tidal and non-tidal wetlands, inland marshes and fens, and along lakes and rivers. It is also found in disturbed sites where soil has been exposed to high nutrient inputs, such as, roadsides, construction sites, agricultural fields or developed shorelines. Phragmites is found throughout the United States and parts of Canada.
Invasive Phragmites lineages can be distinguished from native species by a few morphological characteristics, such as: height, size, stem and leaf color, as well as, appearance of leaf sheath and rhizomes.
Leaf Blade and Sheath: Leaves are dark blue-green in color and are long and strap-like with narrow pointed edges. They are alternately dispersed along the plant stem. The leaf sheath is located at the lower part of the stem and typically is wrapped tightly around the culm (stem). Leaf sheaths adhere tightly to the culm throughout the growing season and persist well into other growing seasons.
Stem: are slightly ridged with a rougher texture than the native and are green in color, and unlike native common reed, invasive Phragmites has few to no fungal spots on its’ stem.
Flowers: form large bushy purple to golden brown plumes that grow to 1-2 feet in length and drape to one side. Flowers bloom in late July and August. Seeds are grayish and are covered with silky hairs.
Ligule: a translucent or hairy outgrowth that is located on the upper leaf surface at the juncture of the leaf blade and sheath. In invasive Phragmites, the ligule is between .4-.9 mm in length (which is smaller than native Phragmites lineages).
Control/Management: All control techniques will need to be repeated annually until there is no sign of infestation. It is important to restore the area by planting native vegetation that competes with Phragmites such as: Jesuit’s bark (Iva frutescens), groundsel-tree (Braccharis halimifolia), and black rush (Juncus roemerianus).
Due to the similarity of non-native and native Phragmites, it is important to properly identify the species before implementing any type of management program. Since Phragmites grows in wetland habitats, it is also important to implement a restoration plan after treatment to reduce the potential for soil erosion. Phragmites can be controlled physically, mechanically and chemically.
If chemical control isn’t an option, using hand tools to control Phragmites, yet cumbersome, it is an effective technique . Since Phragmites is a form of grass, cutting it above the stalk can stimulate growth. It is best to cut the stalk below the soil surface using the blade of a spade shovel. This technique works best on small stands in sandy loose soils. CLICK HERE to view this technique.
If the soil is too compact and you can’t cut the stalk below the soil surface, cut the stalks below the lowest leaf leaving no more than 6 inches of stalk above the ground. If you chose this techniqe it is imortant that you cut the stalk in late July to reduce stimulating its growth.
Mechanical Control: repeated mowing can produce short-term results; repeated stem breakage in high-water years has also shown to eradicate large portions of Phragmites colonies. These methods require repeated application as broken plant fragments can generate a new plant.
Chemical Control: Newer colonies that have smaller root and rhizome systems are easier to control using herbicides. Chemical applications are best applied in late summer or early fall after the plant has flowered. Applications can be foliar, cut stump or injected. Multiple years of treatment may be necessary to eradicated surviving rhizomes. It is important to follow specific herbicide control guidelines which can be found at the National Parks Service website.
Title photo: Jill Swearingen, USDA National Park Service, Bugwood.org; Habitat/distribution map: USDA Plants Database. Phragmites Native Vs. Non Native: Rob Williams, SLELO PRISM. Leaf blade/Sheath,flower and ligules photo: gobotany.newenglandwild.org. Stem photo: illinoiswildflowers.info.
Learn about Phragmites control techniques: http://www.greatlakesphragmites.net/management/techniques/
To address Phragmites management/control challenges, the Great Lakes Phragmites Collaborative is developing an adaptive management strategy called The Phragmites Adaptive Management Framework (PAMF). This framework will change the way Phragmites management is done throughout the Great Lakes basin and lead to approaches that maximize the effectiveness and efficiency of Phragmites management. To learn more CLICK HERE.
“Common Reed (Phragmites Australis (Cav.) Trin. Ex Steud.).” New York Invasive Species Information. Cornell University, n.d. Web. 28 July 2015. <http://www.nyis.info/index.php?action=invasive_detail&id=42>.
“Invasive Species: Aquatic Species – Common Reed (Phragmites Australis).”Invasive Species: Aquatic Species – Common Reed (Phragmites Australis). United States Department of Agriculture, n.d. Web. 28 July 2015. <http://www.invasivespeciesinfo.gov/aquatics/commonreed.shtml>.
“Native vs. Invasive?” Great Lakes Phragmites Collaborative. N.p., 08 Oct. 2012. Web. 28 July 2015. <http://greatlakesphragmites.net/basics/native-vs-invasive/>.
Swearingen, J. and K. Saltonstall. 2010. Phragmites Field Guide: Distinguishing Native and Exotic Forms of Common Reed (Phragmites australis) in the United States. Plant Conservation Alliance, Weeds Gone Wild. http://www.nps.gov/plants/alien/pubs/index.htm