Forest Insect and Disease Newsletter

Invasive Plants

Oriental Bittersweet

photo:Oriental Bittersweet extensive vines

Photo 1

photo: Oriental Bittersweet vine

Photo 2

Since it was first found in Minnesota last fall, Oriental Bittersweet has been found at several other sites in the southeast portion of the state. But the infestations are still few and far between, so in most cases management efforts are warranted. So watch for it and if found, contact your nearest DNR forester.

This is a really nasty plant producing extensive vines (See photo 1) that are so heavy that they can bust up a mature tree and smother small trees and shrubs, killing them (See photo 2). Vines can reroot when they touch the ground starting new plants. Underground rhizomes can spread up to 65' away. Birds eat the berries and spread the seed. People attracted the red berries surrounded by bright orange bracts, gather them for ornamental purposes and accidentally spread the seed that way. Oriental bittersweet can also hybridize with the American bittersweet, displacing it from its native habitat.

It is very difficult to tell American bittersweet from Oriental bittersweet by its leaves (See photo 3) alone. But how the leaves expand in the spring and the color and distribution of the berries distinguish the native from the exotic species. Oriental bittersweet leaf buds swell and then open like two halves of a book. American bittersweet leaf buds emerge as a slender shoot with leaves that unroll like a Venetian blind. Female Oriental bittersweet plants produce berry clusters at multiple leaf axils (See photo 4), while American bittersweet produces berry clusters only at the terminal end of their branches. Male

plants do not produce seed in either species, so may be difficult to identify. More information

photo: Oriental Bittersweet leaves

Photo 3

photo: Oriental Bittersweet

Photo 4

'Invasive Species' as theme at the State Fair

The theme this year in the Department of Natural Resources (DNR) building at the Minnesota State Fair will be invasive species. So besides lots of information at the various information booths, there will be a number of presentations and shows on the DNR stage. Come September 1 to learn all about the emerald ash borer. On September 3, aquatic invasive species will take the stage, while the presentations on September 4 will be dedicated to terrestrial invasive species. Presentations are scheduled for 11:00 a.m., 1:00 p.m., 3:00 p.m. and 5:00 p.m. So come join in the fun.

image: Invasive webpageNew invasive species webpage

The Division of Forestry has created a new webpage for their invasive species program. Visit the webpage to see what the Division has been up to. You'll find a number of excellent resources as well as links to related programs, such as the DNR Firewood Program.

image: Brochure cover of Invasive species management workshopUp Coming Workshop

The Minnesota Invasive Species Council and Minnesota Chapter of the Soil Water Conservation District are co-hosting a traveling workshop on invasive species management. The workshop will be held in the Detroit Lakes area on August 18. Meet at 8:45 a.m. in Minnesota State and Technical College, Room C103, 900 Hwy 34 East, Detroit Lakes, MN, 56501. For more information contact Rhett Johnson @ 218-498-2679 or Shannon Carpenter @ 320-983-2154 or visit their website at Website:

Branding Project

This month, the Division of Forestry is launching a project to develop a brand and marketing plan meant to foster recreation behaviors which will help stop the spread of terrestrial invasive species. Project administrators were thrilled when Ivarson Brand Visions won the bid to do the creative work on the project. Ivarson Brand Visions has extensive experience in brand development and had previously worked for the US Fish and Wildlife Service to produce the Habitatitude and Stop Aquatic Hitchhikers brands. The success of these two projects was clearly demonstrated in the results of the focus groups carried out last year. When asked to name a land-based (terrestrial) invasive species, recreationists were more likely to mention zebra mussel and Eurasian milfoil than any of the more common land-based species such as emerald ash borer or buckthorn. Stay tuned.