BLM completes mitigation on invasive Phragmites australis near Great Salt Lake

SALT LAKE CITY — The Bureau of Land Management’s Salt Lake field office recently conducted work to diminish the impacts of Phragmites australis, an invasive species near Great Salt Lake. 

In a recent Facebook post, the BLM wrote that they mowed the area. Later this year, the Bureau said they plan to apply herbicide. 

BLM officials hope their efforts will prevent the invasive species from outcompeting native plants along the lake’s shoreline. In the future, they hope invasive species mitigation will help native plants flourish and restore the habitats in the area. 

BLM treatments aren’t the first efforts to control Phragmites australis. A post on the Utah Division of Forestry, Fire and State Lands website said efforts were made near Great Salt Lake and Utah Lake in 2022. 

At that time, the Division of Forestry, Fire and State Lands noted a 65% reduction in growth near Great Salt Lake. On the shores of Utah Lake, they noted a 74% reduction. 

The BLM’s recent post did not mention current levels of reduction or growth. 

Phragmites australis 

According to the United States Department of Agriculture, Phragmites australis is often called the common reed. 

Some strains are native to the U.S., however, the USDA believes invasive strains came from Europe sometime in the 1800s. 

KSL.com previously reported that Phragmites australis ended up in Great Salt Lake in the 1980s. At the time, floods were damaging surrounding areas, while also washing Phragmites australis into the water. 

To ease the risk of flooding in communities near the lake, experts pumped water out of the lake. However, it was too late to prevent growth. 

Utah State University Extension called Phragmites australis “aggressive, tall, [and] dense.”

Once the weeds have established themselves, their roots can grow as deep as 10 feet, reaching groundwater. The dense stands can sprout as many as 60 tall stems within a square foot. 

Additionally, they grow quickly, expanding by as many as 20 feet per year and growing as much as an inch and a half per day. 

They aren’t only problematic on the shores of Great Salt Lake and Utah Lake. According to USU, they have also established themselves in smaller areas and along the Jordan River. 

How are experts controlling the invasive species? 

According to a presentation published by the Utah Division of Natural Resources and the Jordan River Commission, researchers recommended a combination of three methods for controlling Phragmites australis: 

• mowing
• herbicide application, and
• revegetation.

While mowing and herbicide work to remove them, revegetation helps native plants recover according to the DNR presentation. 

USU Extension explained that cattle grazing has been examined as an alternative removal tool. Allowing cows to graze on Phragmites australis is cost effective and requires minimal labor, according to USU Extension. 

For example, USU said that mowing often costs land managers about $100 an acre. In comparison, they may able to earn money from ranchers based on grazing fees. 

Additionally, it doesn’t only take care of removal. It also helps break up the plant matter. 

Despite the benefits of cattle grazing, it can’t be used everywhere. Per USU, grazing can only be included in removal plans when water can be lowered and cattle have limited access to native plant species. 

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