Introduced
Species Summary Project
Common Reed
(Phragmites australis (Cav.) Trin. Ex Steud)
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Scientific
Name: Phragmites australis (Cav.) Trin. Ex
Steud 
Classification:
Phylum or
Division: Angiosperm
Class: Monocot
Family: Poaceae
Identification: The common reed is a tall perennial grass with an
approximate height of 15 feet or more and forms dense stands with about 19
steams per square foot both dead and alive. It has horizontal stems (Rhizomes),
which annually send out stiff vertical shoots that are stiff and have sheath
like leaves. The shoots and leaves are stiff and sharp due to high amounts of
cellulose and silica. The flower stem is about one foot long with many feathery
branches. Each individual flower is about 1/2 an inch in length. Common reed
can sprout from rhizomes or seeds and some colonies can be hundreds of acres in
size.
Phragmites tends to prefer sunny wetlands and is also found in
areas of moist soil in fresh or brackish water marshes. It can be found along
riverbanks and lakeshores. It grows in areas of disturbed soil, ditches,
roadsides, and other areas of degradation. The only thing limiting its growth
is high salinity. It is interesting to note that while Phragmites is a native plant to the United States what has made it
so invasive is that it finds a niche in any disturbed area, and can easily out
compete any other species vying to reestablish it self in the same disturbed
area.
Original
Distribution: Phragmites is
native to the Americas
Current Distribution: Canada to
South America only in greater abundance.
Site and
Date of Introduction: Phragmites
is native to North America therefore there is no specific introduction site or
date. Phragmites occurs any place
humans have disturbed or degraded the topsoil or environment in an area with
favorable growing conditions. There are currently studies being done on the
possibility that in the early 20th century a more genetically
aggressive strain of Phragmites came
in from abroad.
Mode(s) of Introduction: Phragmites is a prolific seed spreader
and soil movement easily deposits its rhizomes, by soil moving equipment,
animals, water, or happenstance.
Reason(s)
Why it has Become Established: Phragmites is one of the most opportunistic organisms in the
western hemisphere. Any disturbed area with favorable growing conditions will
support it. Phragmites can easily
takeover an area when there is environmental stress, such as altered hydrology,
restricted tidal flooding, storm drainage ditches, storm water discharges, road
salt and water pollution. These factors have helped Phragmites to establish itself in nonnative niches.
Ecological Role: Phragmites produces beautiful stands and
are valuable to wild animals such as nesting ducks, herron and egrets. Phragmites also provides good cover for
deer. Phragmites provides good forage
when stalks are still young and tender and birds feed on their seeds. Phragmites generally is monodominant but
occasionally is found with bulrush, cattail, arrowhead, northern redgrass and
sedge.
Benefit(s): Soil
stabilization, revegitation projects, control of shoreline erosion,
stabilization of stream, river and canal banks, grazing, thatching, cellulose
source for paper and textile manufacturing are just some of the benefits of Phragmites.
Threat(s): That Phragmites contributes to the reduction
of biodiversity in wetlands is the primary threat. Invasive stands of Phragmites can quickly replace other
native species such as short grasses, cattails and other native plants. Phragmites also affects marsh habitat of
birds and fish and can create a fire hazard when there is a large amount of
dead biomass.
Control Level Diagnosis: Medium priority should be applied to the
control of Phragmites. But this is
not to say that this is not a serious problem in fact, Phragmites if not controlled will rapidly change the complexion of
the environment and contribute to the reduction in biodiversity in the niches
they takeover and thus, should be taken seriously.
Control Method: Phragmites
can be controlled through many different methods, but the problem is there are
money, timing and pollution constraints that affect these programs.1) The
easiest way to control a portion of the Phragmites
problem is to eliminate restrictive flows in saltmarshes, increased salinity
from this method kills Phragmites. 2)
Cutting, mowing or disking can help the problem. If mowing is done too late or
early it can actually stimulate growth and make denser stands. This method does
contribute to a reduction in fire hazard. Disking is too costly but can work on
a small-scale basis. 3) Herbicides, while they do work, pose another type of
environmental problem killing other grass species and it is also expensive. 4)
Burning can only work if it is a root burn and burning can actually stimulate
growth. 4) Covering with plastic after mowing can have good results after a few
days because of higher temperatures generated under the plastic. This method is
labor intensive. 5) A combination of all these methods along with aggressive
replanting of other native species is the most effective way to inhibit
encroachment by Phragmites.
References
Massachusetts Audubon Society:
Saltmarsh Science Project
Phragmites: Controlling the All-Too-Common Common Reed, Wetlands
Restoration & Banking Program, Massachusetts Executive Office of
Environmental Affairs, Tinner 1995
Phragmites australis, Ronald J. Uchytil 1992
Invasive Plant Council of the
State of New York (IPC), Common Reed - Phragmites
australis, April 13, 2001
Picture(s) may be obtained at http://plants.usda.gov/cgi_profile.cgi?symbol=PHAU7
Author: David
Blinken
Last Edited: 03/07/02
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Project Editor: James A. Danoff-Burg, Columbia University