UAF extension collaborator outlines identification and control options for bird vetch in Wasilla

Gino, a UAF Cooperative Extension collaborator, told the Wasilla Planning Commission on Oct. 14 that bird vetch (a nonnative vining legume) can be identified by its purple flowers arranged on one side of the stem, numerous narrow leaflets on compound leaves and coiling tendrils that allow it to climb trees, fences and other structures. "Bird vetch has those numerous purple flowers...they're all typically on one side of the stem," he said.

Gino summarized the plant's history in Alaska, saying it was planted in experiment stations beginning about 1909 and later used as a green manure and pasture plant before being widely recognized as a weed in the 1980s. He told commissioners that bird vetch spreads along roads and disturbed sites and that maintenance activities—mowing, grading and equipment movement—can move seed or scarify seed in ways that help it establish elsewhere.

The presentation emphasized practical control options and their limits. For early, light infestations Gino recommended manual removal and repeated pulling, noting that "if you're gonna be doing this over a whole area, you gotta start really cooperating with different landowners, different land managers." He described repeated mowing (twice a year) and improved grass competition as cultural approaches that can keep vetch in check but not eliminate deep infestations. He advised that weed-barrier fabric can work on some sites but often requires edge treatment for resprouts and may need to be maintained for multiple years because the seed bank is suspected to persist about five years in soil.

On chemical control, Gino said systemic herbicides that translocate to the root are the most effective for long-term control, and he advised treating new spring growth in late May through June for best results. He cautioned that herbicide choice must match the site (residential yard, roadside, wetlands or pasture), and that some active ingredients are unsuitable near certain trees or in sensitive landscapes. "You really kinda wanna get at the root system if you wanna do more than basically mowing it," he said.

Commissioners and residents asked about alternative tactics. Gino said goats or intensive grazing can suppress vetch in contained areas ("you could do that; it would be basically like mowing it"), but are generally impractical on road rights-of-way. He recommended cleaning mowing/maintenance equipment after working in infested areas to limit seed transfer. For disposal he advised that plant material without seed can be composted, but material with seed should be double-bagged and placed in the trash; he said municipal landfills commonly bury such waste.

Acting City Planner Nygaard said staff has been coordinating with the Wasilla Soil and Water Conservation District, the Alaska Department of Transportation (DOT) and the railroad on invasive-plant management plans. Nygaard said the city has obtained small seed funding to pilot a few high-visibility right-of-way projects over the winter and urged stakeholders to collaborate on any larger coordinated efforts.

Residents described heavy local infestations, including tall vines in trees around Wasilla High and new encroachment along lake shorelines; one resident said she has been "fighting it ever since" she bought her property five years ago. Commissioners urged staff to track opportunities for targeted control in parks, rights-of-way and new subdivisions before vetch becomes established.

The commission thanked Gino for the presentation and encouraged people who missed the meeting to view the streamed talk.