What is oriental bittersweet?

Oriental bittersweet identification is easiest in late fall: yellow-orange husks split open to reveal bright red berries strung all along the vines. It’s a woody vine from eastern Asia, brought over as an ornamental, that now covers wood edges and hedgerows across Pennsylvania.

It’s a Class B noxious weed in the state. The vines twine tightly around tree trunks, eventually girdling them, and pile up in the canopy until the weight brings branches or whole trees down in ice and wind storms.

Oriental bittersweet identification: what to look for

• Leaves: alternate, glossy and finely toothed, 2 to 4 inches long. Lower leaves are almost round, while upper ones are more oval. They turn bright yellow in late summer or early fall, often before native trees change color.
• Flowers: small and yellow-green in late spring, clustered in twos or threes where leaves meet the stem, all along the vine.
• Fruit: round berries with a yellow-orange outer skin that splits to show a scarlet center. They grow all along the stem and hang on through winter, so birds keep spreading them.
• Stems: bright green when young, maturing to light brown, cracked bark. Vines twine without tendrils, sticky pads or hairy roots, and older vines can be several inches thick.
• Roots: pull a seedling and the root is a striking bright orange.

Where it grows in Pennsylvania

Oriental bittersweet grows best in sun but tolerates shade when young, so seedlings wait under the trees until a gap opens. It’s everywhere in central PA: along wooded lot lines, old fence rows, abandoned fields growing back to woods, road edges and the steep, rocky banks no one mows.

Birds eat the berries and drop the seeds under perches, which is why it often shows up under fences, power lines and along the edge of the woods behind your house. Once a vine reaches the treetops it fruits heavily, and the cycle speeds up.

Oriental bittersweet look-alikes

• American bittersweet is a native vine that has become rare. Its flowers and fruit grow only at the tips of the branches, its fruit husk is red-orange rather than yellow, and its leaves are more pointed and football-shaped. The two can hybridize, and nurseries have mislabeled them. If fruit lines the entire vine, it’s the invasive one.
• Japanese honeysuckle twines the same way but has opposite, smooth-edged leaves, white-and-yellow flowers and black berries.
• Poison ivy also climbs trees, but it has three leaflets, white berries and fuzzy aerial roots. Check before you grab a vine with bare hands.

How to get rid of oriental bittersweet

Killing bittersweet means going after the root system. Cutting alone just makes it resprout, so plan on cutting first and treating what grows back.

Hand and mechanical:

• Pull small seedlings, getting the orange root. This works best in moist soil.
• On vines climbing trees, use a “window cut”: cut each vine near the ground and again at about eye level. That frees the tree right away. Don’t yank cut vines out of the canopy; it can break limbs or bring down dead wood on you.
• Expect resprouts. Cut again or treat them, season after season, until the roots give up.
• Mowing alone tends to make root suckers multiply.

Cultural: once the vines are cleared, replant openings with trees and shrubs and keep an eye on edges. Bittersweet thrives on disturbed, sunny ground, so leaving a cleared area bare invites it back.

Herbicides: Penn State Extension lists triclopyr and glyphosate as the main tools. Treating freshly cut stumps right away, or applying an oil-based triclopyr product to the lower bark of smaller stems, can be done much of the year. Foliar sprays on regrowth work best from July until fall color starts, usually at least eight weeks after cutting. Read and follow the product label every time; the label is the law. Check that the product is labeled for your site, whether that’s a lawn, a landscape bed, woods or ground near water, where only aquatic-labeled products belong. Applying herbicide for hire in Pennsylvania requires a PA Department of Agriculture pesticide applicator certification, so bigger jobs belong with a licensed vegetation-management company.

Keeping it from coming back

Birds will keep dropping seeds from neighboring properties, so check the wood line every year, especially in fall when the yellow leaves make it easy to spot. Pull seedlings while they’re small.

Don’t use the berries in wreaths or decorations, since the seeds spread when you throw them out. If heavy vines have already damaged trees near your house or driveway, have those trees looked at before the next ice storm.

On a large wooded lot, work in stages. Free the trees you care most about first with window cuts, then clear the worst thickets, then come back each year for resprouts. Spreading the work out keeps it manageable and gives replanted shrubs and trees time to fill in.

Questions we get about oriental bittersweet

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