Common reed (Phragmites australis australis) is a perennial, wetland grass with subspecies both native and introduced to the United States. The native subspecies (Phragmites australis americanus) is not invasive and does not cause problems for other wetland plants native to Missouri. This page therefore addresses only the introduced, invasive common reed subspecies (Pharagmites austrails australis).
Common reed produces tall, hollow stems that can reach heights of up to 15 feet. It occurs in disturbed or pristine wet areas, including wetlands, shores of ponds and lakes, marshes, springs, riverbanks, roadsides and ditches. Common reed grows best in areas with slow or stagnant water and can tolerate frequent, prolonged flooding, seasonal drying, and moderate salinities.
Effects on Natural Communities
Common reed usually spreads by above-ground stolons (lateral shoots that root to form new plants) and below-ground rhizomes. Its vigorous rhizomatous growth frequently becomes dense and often impenetrable. This alters the diversity of natural wetland communities. The thick litter accumulation and dense vegetative growth prevents native plant species from growing and can alter the area’s hydrology. Wetland wildlife habitat is substantially degraded.
The most effective control for common reed is the use of foliar-applied herbicides. Imazapyr and glyphosate, alone or in combination, are effective at a 1.5 to 2 percent solution. These systemic herbicides are absorbed by the foliage and translocated to the rhizomes. Herbicide treatment can occur from June to September, when plants are actively growing.
For small infestations, utilize the cut-stem method from mid-summer until fall. Individual stems should be cut below the lowest leaf, with a 25 percent glyphosate solution applied into the stem and around the cut edge. If applying near or in water, use a glyphosate formulation that is approved for aquatic use.
Due to vigorous re-sprouting, mechanical control methods, such as cutting, mowing, and fire are often ineffective when used alone, but can be used in conjunction with herbicide application. Exposed rhizome fragments may freeze and dry out over the winter, reducing the density of the stand. Retreatment over several years may be necessary due to the extensive root system.
Learn the Difference between Native and Nonnative Common Reed
The subspecies of common reed are difficult to distinguish using physical features alone. However, the following characteristics of the invasive common reed subspecies (Phragmites australis australis) can help to identify it:
- Robust wetland grass up to 15 feet tall, somewhat rough to touch
- Numerous long, flat leaves that exhibit a darker gray-green color
- Stems more green and without the red coloration
- Leaf sheath is retained and wrapped around stems in winter
- Flowers in large, bushy panicles, purple to golden in color
The native common reed has leaves that are lighter and yellowish-green, and stems that are often red or maroon. The native common reed subspecies is found more commonly in undisturbed sites.