Common reed grass or Phragmites (Phragmites australis), is a perennial grass and is thought to be one of the most widespread plants on Earth. It is believed to have originated in the Middle East. Genetic research suggests that there are three separate lineages of Phragmites australis 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 are spread by seed and rhizomes and are 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 outgrow and out-compete 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 that rely on wetland ecosystems for survival.
Phragmites grow 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 the soil has been exposed to high nutrient inputs, such as roadsides, construction sites, agricultural fields, or developed shorelines. Phragmites are 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, the 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 their’ stem.
Inflorescence: 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. Invasive Phragmites have a ligule that 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 grow 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 is an effective technique. Since Phragmites are a form of grass, cutting it above the stalk can stimulate growth. It is best to utilize the “Spading Technique,” and 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 technique it is important that you cut the stalk in late July to reduce stimulating its growth.
Another technique for non-chemical management in a small infestation would be to smother or utilize the “solarization technique”. A thick black tarp is placed over a small infestation which blocks the sun and generates a high heat which eliminates the plant’s ability to grow. Regular garden fabric will not work for this. This is a technique often used in gardens for nuisance weeds and is often considered a more eco-friendly method, though any native species existing under the tarped area will be impacted. It is estimated that this method can take a few years to be successful, as with most other techniques.
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 on the National Parks Service website.
Restoration at Your Site
The Eastern Lake Ontario Dunes and Wetlands complex (ELODW) offers important habitats for a variety of animal species and unique vegetation as well, all of which depend on intact and healthy ecosystems for survival. It is important to take care to not negatively impact but to promote native biodiversity, and one way to do this is by connecting management with restoration. Ecological restoration is the process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed, in this case, by invasive species like Phragmites.
It is important to ensure that while conducting restoration at sites, you’re not introducing additional non-native or invasive species. One way to select the most appropriate species is by choosing native species and even better, those that already exist on your property. Before you select new species, you should take your geographic area, soil type, water conditions, nutrients, drainage, etc. into consideration. Many citizen science-based tools exist that can help identify species on your property, two recommendations include iNaturalist online or via the app and Seek by iNaturalist, an app that uses image recognition technology to identify the plants and animals all around you. Visit the SLELO website to learn more about promoting native biodiversity in your project sleloinvasives.org/educational-material.
Photos are very important in any project for comparing results. Be sure to capture your progress and share it via social media or with SLELO PRISM.
Title photo: Jill Swearingen, USDA National Park Service, Bugwood.org. Phragmites Native Vs. Non-Native: Rob Williams, SLELO PRISM. Leaf-blade/Sheath,flower and ligules photo: gobotany.newenglandwild.org. Stem photo: illinoiswildflowers.info.
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