Common reed is a tall, perennial grass that can grow to heights of 15 ft. (4.6 m) or more. Broad, pointed leaves arise from thick, vertical stalks. Leaves are 6-23.6 in. (15-60 cm) long, 0.4-2.4 in. (1-6 cm) wide, flat and glabrous. The flower heads are dense, fluffy, gray or purple in color and 5.9-15.7 in. (15-40 cm) long. Flowering occurs from July to October.
Common reed is usually found in dense thickets growing in or near shallow water. These thickets displace native wetlands plants, alter hydrology and block sunlight to the aquatic community. Exotic common reed is native to Eurasia and Africa. Native Phragmites do occur in the United States and they are sometimes very difficult to distinguish from the exotics. (Source: EDDMapS)
Phragmites is most commonly found in freshwater wetlands but it readily invades salt marshes that have been degraded by some type of flow restriction. In these cases, the most effective treatment is to restore the flow of salt water. Over a period of 10 to 20 years, phragmites will slowly die back and be replaced by salt marsh grasses. In brackish or freshwater wetlands where there is no possibility of introducing tidal salt waters, the following control techniques can be used.
Management Options:
F. Black Plastic
G. Reinforced Geomembrane Barrier
Cutting or pulling has been used successfully to control phragmites. Treatments usually need to be repeated annually.
A. Hand Pulling
Control can often be accomplished by hand-pulling for small populations (less than 1/4 acre). Plants pulled early in the season are much smaller and easier to manage.
B. Cutting & Mowing
Mowing (or brush hogging where woody plants are present) is suited to non-rocky, open areas that are not too steep for the equipment. Obviously, mowing affects all plants mowed, not just the target species. Equipment should be cleaned prior to being brought to the site and should be thoroughly cleaned of all seeds and plant parts before leaving the site.
The best time to cut phragmites is at the end of July. Cutting at other times may increase stand density. Phragmites stems should be cut below the lowest leaf, leaving a 6″ or shorter stump. Hand-held cutters and gas-powered hedge trimmers work well. Weed whackers with a circular blade were found to be particularly efficient but were more dangerous to volunteers (Marks et al., 1993).
Cut or pulled material should be removed from the site and composted or allowed to decay on the upland. Some patches may be too large to cut by hand, but repeated cutting of the perimeter of a stand can prevent vegetative expansion. Cutting can be expensive and labor intensive. In Quincy, Mass., $150,000 was spent to cut 10 acres of phragmites three times one summer using Bobcats mounted with lawnmower clippers. Hand-pulling, though labor intensive, is an effective technique for controlling phragmites in small areas with sandy soils.
C. Propane Torch/Prescribed Burning
Backpack-mounted propane torches can be used for invasive plant control. This method uses targeted fire to heat the base of a plant, killing it. Some plants with developed roots may resprout after this treatment. Safety training is needed before using this method.
Prescribed burning, as a treatment by itself, can actually increase shoot densities and below ground biomass of phragmites. Burns can be effective, however, if followed by flooding in the marsh. Flooding a marsh after a burn requires the capacity to manipulate water levels. Burning has also been used successfully following herbicide applications. All applicable permits and licenses must be obtained prior to conducting a controlled burn. Phragmites fires can burn very hot and fast, and may start spot fires some distance away. This technique, therefore, can be dangerous, and is only appropriate for professional land managers.
D. Herbicides
Herbicides are pesticides used for vegetation management. Herbicides can be a valuable tool in controlling invasive species, but they must be used with caution.
Always read the entire herbicide label and apply herbicides according to label directions. Wear the personal protective equipment specified on the product label and heed any and all environmental restrictions stated on the label.
Most herbicide products, especially those marketed to homeowners and small property owners, are classified as “General Use” pesticides. Only licensed pesticide applicators are allowed to purchase or apply “Restricted Use” pesticides.
Glyphosate is most active in late summer when phragmites is in full bloom. Repeated treatments will likely be necessary. If the plants are too tall to spray, cut back in mid summer and apply glyphosate when regrowth reaches 2 to 3 ft tall. Choose Rodeo formulation for applications in standing water or along a shoreline (a permit from DEEP is required for any pesticide application to a body of water). After 2 or 3 weeks following application of glyphosate, cut or mow down the stalks to stimulate the emergence and growth of other plants previously suppressed.
ROUNDUP [glyphosate (41%)]: 2.5 fl. oz./gal
RODEO [glyphosate (53.8%)]: 2 fl. oz./gal
E. Grazing
Grazing means using animals to eat plants.
F. Black Plastic
After cutting a stand of phragmites, anchor a sheet of black plastic over the cut area using sand bags or rocks. High temperatures under the plastic will eventually kill off the plants. This technique works best when the treated area is in direct sunlight. The following year when the plastic is removed, a few phragmites shoots may return. These can be cut or hand-pulled.
G. Reinforced Geomembrane Barrier
TDeepRoot Phragmites Barrier™ is an impervious reinforced polypropylene geomembrane that prevents the spread of phragmites when installed vertically in a trench dug around the perimeter of a phragmites patch. This barrier is used to prevent phragmites from encroaching into a landscape. Rhizomes and adventitious roots are not able to penetrate the barrier and will subsequently grow in other directions. For more information about this product, contact DeepRoot Partners, L.P., 81 Langton Street, Suite 4, San Francisco, CA 94103. (800-458-7668, deeproot.com)
| Paul Capotosto | Wetlands Habitat and Mosquito Management (WHAMM) Program 2014: Phragmites control Presentation from CIPWG Symposium 2014 |