No one is sure how it got here. Some say it came from Asia, others Europe. But regardless, it has found a home in the Edmonds Marsh where it is slowly but inexorably creating dense stands of tall reeds that are pushing out native vegetation and degrading wildlife habit.

Phragmites australis is found worldwide. The name Phragmites (pronounced in three syllables, Frag-mite-ease) is derived from ancient Greek, roughly translating as “grows in hedges,” a reference to its tendency to form thick stands around waterways and marshy areas.

According to the U.S Fish and Wildlife Service fact sheet, the non-native Phragmites (there is also a mostly rare, non-invasive species native to our east coast) was first observed in North America in the early 19th century in coastal ports in the eastern United States. The rapid spread of Phragmites in the 20th century was probably related to the construction of railroads and major roadways, habitat disturbance, shoreline development and pollution.

Phragmites was first observed in the Edmonds Marsh six years ago, in a small stand in the northeast quadrant. Since then, this stand has grown into a dense jungle of these 8- to 10-foot-tall reeds, so thick that birds, furbearing mammals and even deer cannot penetrate. More recently it has spawned a second stand just south of the viewing area at the end of the boardwalk adjacent to the railroad tracks. The plants are too rough for forage and tend to crowd out other plants that support wildlife.

The plant spreads mostly by deep underground horizontal stems call rhizomes (while underground, rhizomes are actually stems, not roots) and lateral ground-hugging stems called stolons (see illustration).

It can also spread by seeds that are typically water-borne, which is the likely origin of the second stand in the Edmonds Marsh.

Earlier this week, a small group including marsh advocates and elected officials met at the Marsh with Geraldine Saw, Noxious Weed Control Coordinator for Snohomish County, to observe the stands of Phragmites and discuss strategies for control.

Explaining that mechanical control is virtually impossible due to the deep and complex root and rhizome systems, Saw recommends control by chemical herbicides as the safest and most effective method.

“We use Imazapyr, a U.S. Department of Agriculture and Department of Ecology-approved systemic herbicide that targets the roots of the plants,” she explained. “It degrades within three to four weeks, and when properly applied has no significant effect on other plants or wildlife.”

She went on to explain that the county’s team of licensed applicators would apply the herbicide directly to green Phragmites foliage.  The active ingredient is absorbed into the plant and is translocated via its vascular system to all plant tissue – particularly the stolons and nutrient-rich rhizomes – where it kills Phragmites by de-activating a protein found only in plants. Treated plants will begin to yellow, turn brown and die within about 3 weeks.

“We add a blue dye to the spray that allows quick visual determination of where it has been applied,” she added.

She then explained that treating the Phragmites in the Edmonds Marsh would be quick, requiring about two to three hours. The first application will typically kill about 80% of the stand, and a second application during the next growing season generally gets the remaining 20%.

Because Imazapyr can affect other plants as well, Saw recommends application well in advance of the fall rains, thereby minimizing the chance of increased water flows spreading it beyond the target plants before it has sufficient time (three to four weeks) to naturally degrade.

“Summer is already on the wane, so would be nice if we could do this as soon as possible,” she said.

In order for the application to happen, the county needs approval from the City of Edmonds. Saw plans to prepare a letter to the mayor and city council asking for this.

— Story and photos by Larry Vogel