Thursday, July 16, 2015

New Video on Managing Oriental Bittersweet

Over the past 4-5 years Oriental bittersweet, Celastrus orbiculatushas, has become more and more of a problem in Central Pennsylvania woodlands.  It is a perennial twining woody vine imported from Asia that is rapidly replacing the native bittersweet and strangling many of our forest trees in woods and fence rows.  I have been struggling to control it on the Penn State demonstration woodlot in Centre County for some time now and I can't seem to keep up with it.

Just like all invasive plants it is important to identify the plant and deal with infestations early before they become a major problem.  If you are not familiar with this vine here are a couple of resources that will help. 
Penn State Extension: Oriental Bittersweet
PA Department of Conservation and Natural Resources: Oriental Bittersweet

When controlling this plant it is important to prevent it from going to seed.  So, the first step in the process is to cut the larger mature vines as they grow up into the crowns of trees.  It is imperative to use herbicides when dealing with this plant as cutting alone will do nothing to rid your woods of this invasive vine.  Therefore, when cutting the vines be sure treat the cut surfaces with the appropriate mix.  I have found that a 50% surfactant loaded glyphosate solution (ex. Accord XRTII) will provide pretty good control of the roots.  Cut and treat stems outside of the early spring growing season when you may have sap flow.  Cutting and treating is best in mid-later summer as it will provide maximum herbicide translocation to the roots.

Another attribute of this plant that makes it so difficult to control is the fact that it sends up root suckers, spreading by rhizomes.  Following cutting, foliar herbicide applications made in late summer are most effective at controlling the remainder of this plant.  It is recommended to use the same herbicide solution that is used to control invasive shrubs.  A colleague of mine has prepared an Exotic Shrub Fact Sheet which includes this herbicide mixture of triclopyr and glyphosate.  It is important to calibrate your spray equipment before applying this mixture.  Follow the instructions for Simple Sprayer Calibration: Spot Applications outlined here.

The University of Minnesota Extension has recently released an excellent video entitled "Defeating a Killer Vine: Oriental Bittersweet Management."  This is an excellent 5 minute video that covers both ID and control.  Be sure to check it out.

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