Phragmites Australis

Description

Phragmites Australis is an incredibly hardy wetland reed that is native to Europe. Because of it’s extended growing season and persistence into winter, combined with the incredible density at which is can grow, it will create giant monoculture colonies, killing off any competition from native species. It is not notable for being a great host plant, source of food, or shelter for most wildlife. In fact, the density of it’s colonies often render the area effectively off-limits to many animals because they simply cannot make it through the wall of reeds.

It’s tolerance for flooding and brackish water means that it colonizes both freshwater and saltwater wetlands aggressively. This is particularly concerning because wetlands are sources of the greatest biodiversity, and are subject to massive habitat loss in the region even before you account for the amount of remaining habitat being lost to the immense stands of this invasive colonizer.

Identification

Identifying phrag is fairly easy, especially later in the season. Although there is a native species of phragmites (subspecies Americanus), there is a significant enough difference that you should be able to tell them apart fairly easily.

The first telltale sign is growing density. Invasive phrag grows in incredibly dense stands, which choke and shade out any other plants in the area, forming large monoculture stands. Native phrag doesn’t grow nearly as densely, and thus will typically be found growing among other plants rather than in their own dense stands.

The next sign to look for is color. Invasive phragmites will have blue-green leaves, while the native will be more green-to-yellow. Native phragmites will also have distinctive red bands near the leaf nodes (called culms). Invasive phrag will lack these.

Additionally, size and persistence are good indicators. Invasive phrag grows incredibly tall for a grass, frequently more than 10 feet, sometimes up to 15 feet. Native phrag will typically grow to a more modest 5-6 feet. One of the defining characteristics that aid Australis in so easily outcompeting other native plants is it’s persistence. It will begin growing earlier in the season than almost anything, and after the growing season has long finished, you will still see the light-brown stalks with large seedheads swaying in the winter winds. If everything else around has died back for the winter, but the phragmites is still standing tall, it is certainly Australis.

Removal

Removal of Phragmites Australis is very difficult for a number of reasons. The primary issue is it’s rhizomatous growth. The reason Australis is able to form such dense stands is because each growing season, a single stem can send out underground runners in each direction, up to 10 feet in a growing season, from which many new stalks will grow. These rhizomes can grow several feet under the ground, and when nearby stalks are ripped up, they will simply send up new stalks to replace them.

Unfortunately, once a phragmites stand has established, successfully pulling up these rhizomes is effectively impossible. Without devoting immense time and manpower, the only reasonable way to successfully pull them up is with heavy machinery. Unfortunately, this massive disturbance of the soil creates the perfect environment for phragmites seeds to germinate. Even if you managed to eliminate all the seed heads from the plants you removed without dropping any seeds, seeds from previous years will remain in the soil, and remain viable.

Invasive phragmites stand. Notice how densely packed they are, and the lack of any other vegetation. This is a telltale sign of invasive phrag.