These flowering plants brighten the roadside view with lush purples, bright yellows and pure whites. Even their names are pleasing: bird vetch, white sweet clover and oxeye daisy. Yet these and other plants are no beauties. They are invasive weeds and are changing Alaska’s landscape as they spread. 

Ruth Gronquist, a wildlife biologist and Fairbanks District weed coordinator for the Bureau of Land Management in Alaska, educates the public about the threats invasive weeds pose to Alaska. One of those invasive weeds, white sweet clover, is spreading above the Arctic Circle and along Alaska’s 414-mile Dalton Highway, in particular. This aggressive weed propagates by dropping hundreds of thousands of seeds that remain viable in the soil for decades. It eventually chokes out native vegetation along highways, trails and rivers.

In March 2008, Gronquist gave the BLM-Alaska Resource Advisory Council an overview of BLM’s weed-management strategy for the Dalton Highway Management Area. Afterward the council, a citizen-based group that provides BLM with advice on public-lands management, wanted to view the area firsthand. Five months later, Council members took a fieldtrip to Coldfoot and the Dalton Highway to see the impact of white sweet clover and bird vetch.

The trip began near Coldfoot Camp on the Dalton Highway above the Arctic Circle. Gronquist and BLM intern Rehanon Nehus met the council members at Rosie Creek, just south of Coldfoot. BLM-Alaska State Director Tom Lonnie, Fairbanks District Manager Bob Schneider and other BLMers also joined them at the site. There, 250 miles north of Fairbanks, began a morning of invasive-weed education and weed pulling.

The group donned safety vests for visibility and knee pads for protection and then went to work pulling weeds. The work crew filled eight large trash bags with approximately 480 pounds of white sweet clover and bird vetch. Gronquist explained that instead of dumping the weeds in a landfill, the crew burns the bags and contents.

White sweet clover grows in the soft shoulders of the highway where traffic and wind carry seeds to new areas. The clover now grows as far north as Coldfoot. Gronquist is concerned that the clover will soon take hold on stream banks where currently no invasive plants exist.

Just like the clover that grows in suburban lawns, white sweet clover alters the nitrogen level in the soil, making it unfit for some plants to populate. But unlike the lawn variety that grows as small plants close to the ground, white sweet clover can grow several feet tall in just a couple of years. Its stem and root ball resemble the size of an adult’s wrist and fist, and each mature plant produces thousands of seeds.  Alaska’s wild animals do not eat white sweet clover, which is moderately toxic to animals if they ingest it.

White sweet clover is a biennial plant; so eliminating the first-year plants before flowering is the best time to attack the problem.  Although labor intensive, hand weeding is currently the most effective solution because the white sweet clover is still contained along the shoulders of the Dalton   Highway. Removing second-year plants, taproot and all, before they go to seed is also highly effective.

Concern for the future is that white sweet clover and other invasive plants will choke out the indigenous vegetation. Their sheer numbers and ability to alter soil moisture and chemistry will shade out native plants or inhibit germination. Combine the rapid growth and spread rate of invasive weeds with a warming climate, and problems could lie ahead for the Alaska’s arctic and boreal ecosystems.

Gronquist will return to the field-trip site this summer to monitor and study the effectiveness of the weed-pulling efforts.  This hands-on expedition gave the council members a better understanding of this important program and the challenges BLM-Alaska faces as it manages public lands in the Arctic.

For more information about BLM-Alaska’s invasive weed programs, visit the Web site: http://www.blm.gov/ak/st/en/prog/noxweeds.html.