European Common Reed - Phragmites australis ssp. australis
State Rank Reason (see State Rank above)
In Montana, Phragmites australis ssp. australis has been found in Hill County and other unconfirmed reports need to be verified. Since 2015, the Montana Department of Agriculture has listed it as a noxious weed (MDA 2017). Populations form large, dense monotypic stands, outcompeting other plants. A conservation status rank is not applicable (SNA) because exotic plants are not a suitable target for conservation activities.
PLANTS (species level): Cool season, rhizomatous perennial. Stems 1.5-3.5 m, forming dense stands (Lesica 2012).
LEAVES (species level): Blades 2–4 cm wide, flat and lax to ascending; sheaths with overlapping margins; ligules hairy, 3–6 mm long (Lesica 2012).
INFLORESCENCE (species level): A plumose panicle 15–32 cm long. Spikelets 11–14 mm long, with 3 to 8 florets, the florets covered by silky hairs from the rachilla; glumes shorter than the florets. Lemmas hairless, with an awn-like tip; the rachilla with long silky hairs; palea well developed. Disarticulation above the glumes; unit of dispersal the floret (Lesica 2012).
In Montana, common reed consists of two subspecies (ssp.): ssp. americanus is native and more common while ssp. australis is introduced and very localized. Populations can be easily identified to the subspecies level (see diagnostic characteristics).
The MTNHP is tracking locations of common reed grass at the subspecies level. It is possible that both subspecies can be found adjacent to each other, yet be distinguishable. Consider submitting your observation data to MTNHP.Phragmites australis subspecies americanus is native
[Adapted from Michigan State University Extension (no date)]:
STEM COLOR/LEAF SHEATHS: Sheaths easily fall off, exposing the stem which will turn bright red when exposed to sunlight.
LIGULES: The width of the ligule membrane (not including the fringe of hairs at the top) is the critical measure. The ligule membrane is slightly wider, ranging from 0.4-1.0 mm tall.
GLUMES: In a spikelet, the first (or lowest) glume is relatively longer, ranging from 4-7 mm.
GROWTH FORM: It is less robust, typically reaching 6 feet. It grows a bit more scattered, allowing for light to penetrate through the canopy and for other plants to colonize. Where nutrient availability is high, it will grow denser and taller. Stems break down easily over winter, allowing for other plants to grow.Phragmites australis subspecies australis is exotic
[Adapted from Michigan State University Extension (no date)].
STEM COLOR/LEAF SHEATHS: Sheaths cling tightly to stem, covering the dull, tan stem. It grows stolons, which are horizontal stems that spread on the soil surface.
LIGULES: The width of the ligule membrane (not including the fringe of hairs at the top) is the critical measure. The ligule membrane is slightly narrower, ranging from 0.1-0.4 mm tall.
GLUMES: In a spikelet, the first (or lowest) glume is relatively shorter, ranging from 2.6-4.2 mm.
GROWTH FORM: It forms dense monocultures, outcompeting native species. Stems can grow to 18 feet. Where nutrient availability is high, it will grow denser and taller. Stems do not break down slowly, maintaining a thick thatch.
Sterile specimens of Phragmites
are superficially similar to Arundo
, a weedy, non-native species that gets as far north as Malheur County, Oregon (Lesica 2012). The genera can be distinguished based on glumes. The glumes of Phragmites
are glabrous and shorter than the lemmas. The glumes of Arundo
longer than the florets and covered with soft, whitish hairs 6-8 mm long.
Phragmites australis is found on every continent except Antarctica and may have the widest distribution of any flowering plant (Tucker 1990). It is common in and near freshwater, brackish and alkaline wetlands in the temperate zones world-wide. It may also be found in some tropical wetlands but is absent from the Amazon Basin and central Africa. It is widespread in the United states, typically growing in marshes, swamps, fens, and prairie potholes, usually inhabiting the marsh-upland interface where it may form continuous belts (Roman et al. 1984). As of 2017 it has been been found in a few locations in north-central Montana.
For maps and other distributional information on non-native species see:
Nonindigenous Aquatic Species Database from the U.S. Geological Survey
Invasive Species Habitat Tool (INHABIT) from the U.S. Geological Survey
Invasive Species Compendium from the Centre for Agriculture and Bioscience International (CABI)
EDDMapS Species Information EDDMapS Species Information
Observations in Montana Natural Heritage Program Database
Number of Observations:
(Click on the following maps and charts to see full sized version)
Map Help and Descriptions
(Observations spanning multiple months or years are excluded from time charts)
Margins of ponds, marshes, and river floodplains (Lesica 2012). Often where there is disturbance.
Phragmites australis provides food, cover, and nesting habitat for small mammals, muskrats, waterfowl, rabbits, pheasants, song birds, and other animals. (Gucker 2008). The type and the degree of use by native birds and mammals seems to reflect geography, species, and availablity of resources. It can be good thermal cover for white-tailed deer and mule deer. In Montana it provides forage and thermal cover for many species of birds and small mammals. For pronghorn it is considered a fair food source, and for mule deer, white-trailed deer, and elk it is considered a poor food source in Montana. Common Muskrats use stem for food and for nesting material. Waterfowl eat their seeds while Black-capped chickadees (and other birds) eat the scales (Caetococcus phragmitidis) which commonly live on the leaf sheaths. In Montana this species is used by Red-wing and Yellow-headed Blackbirds. In other regions songbirds, Barn Owls, and Red-winged Hawk may use stands for foraging and/or roosting. Plants may also provide habitat for aquatic species, though, the exotic subspecies can also change the ecology of aquatic systems.
Livestock (cattle and horses) may feed on Phragmites australis before it matures; although, some studies report that is has little to no forage value (Gucker 2008). The amount of use and nutritional value might depend upon geography and what other forage is available.
Management of Phragmites australis
is dependent upon the subspecies. It is important to accurately identify the subspecies before implementing any management action. In Montana, land managers are encouraged to maintain and native common reed populations while eradicating non-native populations. The establishment, spread, and increase in abundance of the non-native Phragmites australis
is associated with human-caused disturbances, such as from land development, tidal manipulation, and waterway construction.
The native Phragmites australis
has attributes (rhizomatous and dense growth form) that make can make it desirable in reclamation projects, such as in controlling erosion. Care should be taken to ensure that only the native subspecies is seeded or planted. In Montana, native Phragmites australis
stands appear to be small monocultures that occur in a matrix with other plant communities; however, plants can create enough openings to allow other plants to co-exist.
In portions of the U.S. Phragmites australis
been called an “ecosystem engineer" because dense, monotypic stands can change plant richness, soil properties, sedimentation rates, animal habitat use, and food webs (Gucker 2008). Large stands of Phragmites australis
have been found to decrease plant diversity due to its growth form and ability to trap sediment and collect common reed leaf litter. In New Jersey, Phragmites australis
stands had lower water salinity, depth to water table, and topographic relief than stands dominated by saltmeadow cordgrass and saltgrass in brackish tidal marshes (Gucker 2008). Further these differences were determined to be significant within three years of Phragmites australis
establishment. For a synthesis of studies evaluating impacts or ecosystem changes with respect to Phragmites australis
and various native plant habitats, please consult the Fire Effects Information System for Phragmites australis
In many parts of the U.S. large monocultures of the non-native Phragmites australis
has warranted management actions that includes altering hydrology, herbiciding, applying fire, planting competitive vegetation, and other tactics. It is recommended that Phragmites australis
management be site-specific, goal-specific, and value-driven (Gucker 2008). Further, it is imperative to understand the biological, chemical, and physical impacts at the particular site in order to determine the management strategy and process.
Large, monocultures of Phragmites australis
can be prevented through management actions that encourage competing vegetation and minimize nutrient loads (Gucker 2008). Phragmites australis
spreads faster in areas with high-nutrient availability, particularly where competiting vegetation has been removed or reduced. The timing and intensity of hydrological changes can also impact Phragmites australis
stands. Please consult the Fire Effects Information System for Phragmites australis
(2008) webpage for a synthesis of studies and literature on this subject.
Prescribed fire is not recommended for controlling the Phragmites australis
. Plants grow in wet environments which are often poorly affected by fire and where other native plants are not adapted to fire. Phragmites australis
plants may be top-killed by fire, but their rhizomes usually survive and will re-sprout(Gucker 2008). Unless rhizomes are killed, fire can stimulate re-sprouting (Gucker 2008). In the short-term, fire may decrease plants, but if viable rhizomes remain than stands will re-colonize (Gucker 2008).Useful Links:Montana Invasive Species websiteMontana Biological Weed Control Coordination ProjectMontana Department of Agriculture - Noxious WeedsMontana Weed Control AssociationMontana Weed Control Association Contacts Webpage
.Montana Fish, Wildlife, and Parks - Noxious WeedsMontana State University Integrated Pest Management ExtensionWeed Publications at Montana State University Extension - MontGuides
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?
- Gucker, Corey L. 2008. Fire Effects Information System (FEIS) for Phragmites australis. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer).
- Michigan State University Extension. No Date. Phragmites australis identification pamphlet