Habitat includes: Forests Field and forest margins Meadows and prairie Right-of-ways Fence rows Along waterways Residential landscapes Oriental bittersweet is native to China, Japan, Korea, Mongolia, and the Russian Federation. It was introduced to the eastern US in the 1800s. Image of Oriental bittersweet climbing into the trees on the right and has pulled down the tree in front.
Both sexual (seed) and asexual (rhizome = root that sends up new shoots and stolon = root-like stem that sends up new shoots) reproduction. It can be difficult to identify individual plants due to clonal propagation. Oriental bittersweet is functionally diecious with separate male and female plants. Both male and female plants flower. Male flowers produce pollen that is received by female flowers. Pollinated by insects (bees) and wind. Birds aid the dissemination of seed by eating the fruit containing seed. The seed passes through the bird and can moved to uninfested areas. The seed germination rate is higher after the seed has passed through a bird. Seed viability in soil is not long (generally 1-3 years). A short-lived seedbank is helpful for long-term infestation control. Image of rhizome sending up new shoots Image of summer leaves and fruit.
People use the colorful fruiting vines for arrangements. Seed can be inadvertently dispersed when collecting, transporting, and disposing of the fruiting branches.
Although Oriental bittersweet is newly reported in MN, we can use assessments from the eastern and southern regions to prompt us into action before Oriental bittersweet is widespread. For example, Forest Service ranked Oriental bittersweet #5 of the top 10 invasive plant priorities for the Northeastern Area. Images: Oriental bittersweet vine girdling a tree (left) and a downed tree overwhelmed by bittersweet vines.
This mass of Oriental bittersweet vines climbed into the trees and is beginning to down trees.
When leafed out, Oriental bittersweet shades and smothers other vegetation. The images shows a Colorado blue spruce and fence engulfed by Oriental bittersweet. Infestation along Hwy 36 in the metro. Mn/DOT has controlled this infestation.
Identifying Oriental bittersweet Top left: Leaves are glossy green and leaf shape is highly variable Top right: Raised white bumps (lenticels) on the stem Bottom left: Fruits are positioned at where the leaves attach to the stem (at the leaf axils). Green summer fruits are shown in this picture. Bottom right: Fall fruit with a bright yellow capsule.
Both American and Oriental bittersweet occur in the same habitat. Unfortunately, Oriental outcompetes American because it germinates better in the shade, has a longer period for photosynthesis because it leafs out early in the spring and holds its leaves late in the fall, and Oriental bittersweet can smother American bittersweet. Hybrids were created for a lab study demonstrating that the species can hybridize. Few viable progeny were produced from hybrids and hybrid pollen had a much lower viability compared to the species. Bittersweets with indeterminate characteristics (indicating hybrids) have been observed in the field. The nursery industry developed beautiful cultivars of American bittersweet that are a good choice for landscape use.
The easiest way to distinguish American and Oriental bittersweets is by the fruit capsule color (orange for American and yellow for Oriental) and fruit placement (at the terminal ends for American and at the leaf axils for Oriental).
Reported distribution of Oriental bittersweet in Minnesota. The blue circles with numbers represent clusters of infestations.
First Detector may be asked to collect a plant sample depending on circumstances.
Herbicides containing the active ingredient glyphosate or trichlopyr are used
Oriental Bittersweet Celastrus orbiculatus
Oriental bittersweet <ul><li>Woody vine that climbs other vegetation such trees and structures </li></ul><ul><li>Thrives in a wide range of habitats, light levels, and soil types </li></ul><ul><li>Grows to 66’ in length </li></ul><ul><li>Introduced as an ornamental </li></ul>
<ul><li>Reproduces by seed, rhizome, and stolon </li></ul><ul><li>Male and female plants </li></ul><ul><li>Fruit production on female plants </li></ul><ul><li>Seed dispersal is vectored by birds and other wildlife that eat the fruit containing seed. </li></ul><ul><li>Short-term seed viability </li></ul>Biology
Urtica/Flickr creative commons Human vectored dispersal
Highly invasive and damaging <ul><li>Vines strangle trees, reduce light available for tree growth, and added vine weight can break trees </li></ul>
American bittersweet Celastrus scandens <ul><li>Native congener </li></ul><ul><li>Occur in same habitat </li></ul><ul><li>Oriental bittersweet outcompetes American bittersweet </li></ul><ul><li>Hybrids? </li></ul><ul><li>Cultivars </li></ul>
Distinguishing bittersweets American Oriental Fruit capsule color Fruit position
Oriental bittersweet distribution EDDMapS. 2011. Early Detection & Distribution Mapping System. The University of Georgia - Center for Invasive Species and Ecosystem Health. Available online at http://www.eddmaps.org/; last accessed August 23, 2011.
Report infestations <ul><li>Location information </li></ul><ul><ul><li>GPS coordinates preferred </li></ul></ul><ul><ul><li>Note location for infestations on private property without permission to access </li></ul></ul><ul><li>Digital photographs of the plant (whole plant, leaf, flower, and stem) will aid identification </li></ul><ul><li>Call “Arrest the Pest” or 1-888-545-6684 </li></ul>
Management <ul><li>Outreach and education </li></ul><ul><li>Mechanical and chemical control methods </li></ul><ul><ul><li>Cut and remove vines and dig roots </li></ul></ul><ul><ul><li>Cut stump herbicide treatment </li></ul></ul><ul><ul><li>Foliar herbicide treatment </li></ul></ul><ul><ul><li>Basal bark treatment </li></ul></ul>
<ul><li>Contact Information </li></ul><ul><li>Monika Chandler, 651-201-6537 </li></ul><ul><li>MN Dept. of Agriculture </li></ul><ul><li>[email_address] </li></ul>http://www.mda.state.mn.us/en/plants/badplants/orientalbittersweet.aspx