What's The Issue?
Invasive plants outcompete native vegetation. Loss of native plants reduces available food sources and habitat for wildlife. Two invasive plants that you can find easily in the fall and winter are bittersweet and porcelain berry vines, both of which have distinctive berries that are present this time of year.
In this Protector’s blog, you will learn to recognize bittersweet and porcelain berry vines and the steps that you can take now to get a head start on controlling them before the next growing season. In addition, we’ll share some resources from our Virtual Toolboxes to help you find native plants to grow in areas where you’ve removed invasive plants. This helps to restore the treated area making it more resilient against another invasive plant becoming established and supports wildlife!
Bittersweet (Celastrus orbiculatus) is a deciduous perennial woody vine in the Staff-tree family and is native to eastern Asia. Bittersweet outcompetes trees, shrubs, and other vegetation through climbing and shading. It may also kill trees by girdling them.
Where to Search:
Check your property for woody vines that have bright red berries surrounded by yellow capsules located along the vine. Search along yard edges and near the base and trunks of trees.
Bittersweet reproduces by seed and through vegetative sprouting. Birds feed on and disperse the plant’s fruits aiding in the spread of bittersweet. Discarded wreaths with bittersweet vines are also a pathway for spread as the seeds remain viable even after being dried and can germinate if the wreath is discarded outside.
Bittersweet is widespread in the St. Lawrence Eastern Lake Ontario (SLELO) region.
Stems: Occasionally branching, twining, and up to 4 in. wide. Young stems are green in color and smooth. Mature plants will have reddish-brown colored bark with a cracked, fish-netted texture. Stems don’t have tendrils, barbs, or aerial rootlets as bittersweet climbs by winding itself around the host plant.
Leaves: Alternate, light green in color (turn yellow in fall), oblong to elliptical shaped (highly variable), 2-5 inches long and 1.4-2.0 inches wide with round, fine-toothed margins and a tip that comes to an abrupt sharp point or short taper to a point.
Flowers: Small greenish-yellow flowers with 5 petals that are clustered in leaf axils from May to June.
Fruit: Fruiting occurs from July to October. Fruit starts out green in color and then turns yellow late in summer with the outer layer splitting into 3 parts revealing bright red fruit inside in the fall.
Native Lookalike: American bittersweet (Celastrus scandens) is native and looks very similar to invasive bittersweet (Celastrus orbiculatus). American bittersweet has more elliptical leaves (twice as long as they are wide), while invasive bittersweet is usually more oval (less than twice as long as wide). This difference must be observed with caution since invasive bittersweet leaves are highly variable. A definitive difference is that invasive bittersweet flowers/fruit are clustered along the vine in the leaf axils, while American bittersweet fruits are clustered at the end of the stems. Also, the husk (capsule) of invasive bittersweet fruit is yellow, rather than orange.
Control Options for Bittersweet:
Successful management strategies may require a multi-year effort. Always follow chemical label instructions.
Cut climbing vines at ground level and again at eye level; this provides a visual aid to keep track of what has been cut and where treatments can be applied. All climbing vines should be cut prior to the removal of roots.
Avoid removing vine remains from trees as doing so can damage the tree or cause you injury (cut vines will decompose).
Plants bearing fruit should be burned or bagged and disposed of in a landfill. Monitor the area for re-sprouting and dig them up taking care to remove the roots.
Cut stem treatment: Stems should be cut about 2 inches above the ground and followed immediately by the application of 25% glyphosate or triclopyr solution to the cut stem. Chemical applications are best when applied in the fall when plants naturally draw the chemical to their root system more effectively.
Basal bark treatment: Use an electric trimmer or hand saw to remove enough foliage to expose the bark a few feet off the ground. Apply 20% solution of triclopyr ester in commercially available basal oil with a penetrant to vine stems. Avoid getting herbicide on the host tree.
Foliar treatment: This method should be used for large patches of invasive bittersweet. Apply either 2% solution of triclopyr ester or triclopyr amine mixed in water with a non-ionic surfactant to the leaves. Thoroughly wet the foliage with herbicide, but not to the point of runoff. Foliar applications are best done in the fall when native plants have lost their leaves and target plants will better draw the chemical to their root system.
Porcelain berry (Ampelopsis brevipedunculata) is an invasive woody vine in the grape family and is native to northeast Asia. With the ability to climb over 15 feet in a growing season, porcelain berry easily creates mats of thick twining vines that smother native vegetation. If established in residential or commercial areas, it is difficult to remove from fences, porches, and buildings and can incur costs for property owners.
Where to Search:
Check your property for woody vines that may have a shrub-like appearance with clusters of purple to blue-colored speckled berries with a porcelain shiny look to them.
Porcelain berry reproduces by seed and through vegetative sprouting. Birds feed on and disperse the plant’s fruits aiding in its spread. Another common method in which porcelain berry is spread is by homeowners who intentionally plant it in their yards not knowing that the plant is invasive.
Porcelain berry was reported in St. Lawrence County. The reported population was manually removed and is monitored by our early detection team annually. We need your help to keep an eye out for this plant to ensure it doesn’t become widespread.
Stems/Bark: Young stems are green in color turning a a light brown color covered with raised pores called lenticels. The center or pith of the stem is white. The bark of porcelain berry does not peel off in strips as the native grapevine does.
Leaves of porcelain berry vines vary in shape from a simple heart-shaped leaf with coarse teeth to a deeply lobed leaf with rigid edges.
Flowers are green to white and form in small clusters in mid-summer.
Fruits grow in clusters along the stem. Berries range in color from purple to blue and have speckles and a porcelain-like appearance. Fruits are most apparent in late October on mature plants.
The leaves of porcelain berry are variable ranging from deeply lobed to simple, sometimes both showing on the same plant. The leaves can also be confused with a few native plants including, grape vines and hops. Below is an image showing the subtle differences between each. The first three leaves pictured from the left to the right are porcelain berry leaf variations. The fourth photo from the left is a native hop leaf and the last one on the right is a native grape. View a great video from our partners in Lower Hudson PRISM showing the differences between native grape and invasive porcelain berry vines.
Control Options For Porcelain Berry:
A combination of mechanical and chemical methods is most effective. All courses of treatment should be completed before fruiting occurs to avoid building a seed bank. Herbicide applied in the fall will draw the treatment to the roots more effectively.
Plants can be cut and dug up in the spring when the plants are young and the soil is loose. Stems can also be cut in the fall to reduce growth ability the following growing season. Monitor the area for sprouts and dig up plants and roots. Remove remains with berries and take care to rake up and dispose of fallen berries as seeds can remain viable for multiple years.
Avoid pulling climbing vines from trees as it can damage the tree or cause you injury (remaining vines will decompose over time).
Chemical: Large vines must be cut near the ground and treated with a chemical herbicide or repeated cutting must occur. Garlon 3A, Garlon 4, as well as Roundup and Rodeo, have been used successfully.
Make the areas you’ve removed invasive plants from more resilient by planting native trees, shrubs, vines, and flowers. Check out these resources from our Garden Protector’s Toolbox to get you started!
Visit the Protector’s Virtual Toolboxes below to access resources themed for each category, and to learn more about how to protect your favorite outdoor spaces from invasive species.
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