The stewardship crew has been busy managing more invasive woody shrubs along the Paint Creek Trail and at Bear Creek Nature Park. One invasive woody shrub species we would like to highlight is oriental bittersweet (Celastrus orbiculatus). Bittersweet can be found in a wide range of habitats from woodlands to marshes. It’s a woody vine that will wrap around other plants and trees, covering the vegetation completely and killing them in the process. The twining stems can even climb up to the top of mature trees!
Oriental bittersweet climbs anything it can. The weight of its heavy vines can take down mature trees and smother ground vegetation.
One way to identify bittersweet is by its extensive, bright orange roots. The leaves are alternate along the stem (not in pairs), with toothed margins. The leaves often have a roundish body that tapers to a long tip, but can vary in shape. Its flowers are a pale greenish-yellow and can be found at the base of the leaves along the stem. Bittersweet produces small orange fruits, which makes the vines popular in holiday wreathes.
Ripe bittersweet fruits are attractive with their orange and red contrast, but don’t be fooled! Bittersweet will take over if you throw your holiday wreath in the woods. Photo by iNaturalist user Ganeish, used with permission CC-BY-NC.
This aggressive invasive species can produce large populations from just one seed! Small root fragments can also regenerate, making it difficult to remove completely. Birds and small mammals enjoy the fruits and help this invasive species travel long distances – however the fruits are poisonous to humans and livestock. Don’t spread bittersweet with your holiday wreath!
So if you see the crew out in the parks and would like to learn more about bittersweet and how to identify it, please stop to ask questions!
Natural Areas Notebook 
In the last few years I am now finding bittersweet along my fenceline! I swear it doubles overnight! Very difficult to get rid of but you have to be aggressive with it or it takes over!
Hi Colleen – Your observations match what we’re seeing too. Out in an open field we are finding bittersweet almost anywhere a bird can perch – under shrubs, beneath nest boxes, near trees, and fencelines like yours. It’s definitely wise to control it while you only have a small patch, or it truly does take over!