Phragmites

Phragmites, or common reed has recently become a major pest in Nebraska wetland ecosystems. It is a fast spreading species which grows along, rivers, streams, marshes, floodplains and lakeshores, and has been seen in all 48 mainland states. In Nebraska, Phragmites has begun to overrun most of the ecosystems, especially along the Platte, from Wyoming to Minden and expanding.

Phragmites is a grass species, which has a hollow woody culm or stem that can reach up to 6 meters high. It has lanceolate leaves 20-40cm long and 1-4cm wide that are usually a dark green. The flowering head has silky tufts of hair arranged by tawny spiklets and are wind pollinated.

Phragmites, is a naturally occurring species in North America, however the halophyte (type M) that has overrun these ecosystems is an aggressive European breed. It is likely that the introduction of type M material has occurred in the early part of the 19th century, probably at several Atlantic coast ports. Over the last 150 years, population variation has declined drastically, giving way to this single halophyte throughout the Midwest.

Peat core analyses have found Phragmites australis to be present in N. America for 300 years in tidal plant communities. However, it wasn’t until the late 20th century that this species began invading freshwater and brackish wetlands, making them monoculture. This monoculture has no natural enemies to keep the populations in check and will outcompete other invasives such as purple loosestrife.

Through Rhizomes and stolons, Phragmites proliferates in dense stands of clones. These stands result in changed ecosystem processes and have detrimental impacts on native wildlife. In the Platte River, there are some areas that are being completely choked out by Phragmites. In these areas, hydrology has changed forcing increased sediments and faster, more narrow channels, which decreases habitat especially for migratory waterfowl that use this system. Other channels will be completely lost due to the sediment deposits, forcing this braided river system to only a few channels.

The extremely aggressive behavior by Phragmites is due mostly to the large amount of asexually reproduction through rhizomes and stolons where up to 200 stems per meter squared can be produced. Root can reach from 2-3 meters deep and be very difficult to remove. The inflorescence of these plants does produce a substantial amount of seed but most is inviable. The seed that is viable however forms small stands, which proliferate as clones.

Plant Facts:

Common Name : Common Reed

Growth Form : Grass

Life Span : Perennial

Origin : Worldwide distribution
Invasive halophyte from Europe

Flowering Dates : Early to mid summer

Reproduction : Rhizomes, stolons, and seeds

Height : 1-6 m

Inflorescence : Silky tufts of hair arranged by tawny spiklets

Flowers : Arranged in spiklets (10-15mm long), with 1-6 flowers

Leaves : Alternate, lanceolate in form and attached at stem by smooth sheath

Underground : Rhizomes and deep taproot, extensive 2-3 meters deep

Where Found : Found in 48 mainland states in marshes, rivers, streams, lakeshores, roadside ditches

Uses and Values: Almost no real value as forage has been tested as a source for ethanol production. Erosion control due to deep rhizomatic roots

Poisonings : none

Historical : non-invasive species present in U.S. for 3000 years
Invasive halophyte from Europe

Other : Deep roots make control difficult and has some indication of large water usage. Forces large buildup of sediments along rivers.

Resources:

Cornell. (2005). “Common Reed: Phragmites ausralis.” Ecology and Management of Invasive Plants Program. http://www.invasiveplants.net/phragmites/Default.htm#Taxonomy:.

Saltonstall, K. (2002). “Cryptic invasion by a non-native genotype of Phragmites australis into North America.” Proceedings of the National Academy of Sciences, USA. 99(4): 2445-2449.

Ailstock, M.S.; Norman, C. M. ;Bushman, P.J. (2001) “Common Reed Phragmites australis: Control and Effects Upon Biodiversity in Freshwater and Non-tidal Wetlands.” Restoration Ecology Vol. 9:49-59.