In the Garden:
Middle South
November, 2004
Regional Report

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It's a shame oriental bittersweet is invasive -- the colorful fruits are so festive!

A Bittersweet Story

Just last week, the North Carolina Board of Agriculture reversed its earlier ruling and decided to allow a limited sale of oriental bittersweet (Celastrus orbiculatus) in western North Carolina. Last year, the board had voted to prohibit the sale of oriental bittersweet in the state. The change came in response to concerns about the ban's economic impact on craftspeople in western North Carolina. The rule still prohibits the "movement of oriental bittersweet from specific counties in western North Carolina to other parts of the state."

This has been a contentious debate, with crafts purveyors on one side saying that bittersweet is an important part of their annual revenue, and native plant enthusiasts on the other side decrying this exotic plant's penchant for crowding out native species.

About Oriental Bittersweet
Oriental bittersweet's aggressive habits aren't disputed. The vine is native to eastern Asia and was introduced as an ornamental vine in the late 1800s. The plant found its new home to its liking and has spread beyond the original ornamental plantings to invade natural habitats. Oriental bittersweet's abundant foliage invades tree crowns and weighs them down, making the trees susceptible to damage during wind and ice storms. The vines, which can grow up to 60 feet tall and 4 inches in diameter, frequently girdle and kill their host trees. Advocates of a ban on oriental bittersweet use words like "thug" and "menace" to describe the plant's growth habits.

Bittersweet's ornamental qualities aren't disputed, either. In fall, the bright yellow skin of the abundant fruit capsules splits open to reveal shiny, red, berrylike seeds within. Bittersweet twigs add beauty and character to dried flower arrangements, and, unlike grapevine wreaths, bittersweet wreaths are "pre-decorated."

The beauty of the fruits belies their true purpose, however: to propagate the species. A few berries dropped on the way to the car, a few more at home, a wreath discarded in the brush pile, and you have the makings for a new stand of this invasive plant. Multiply that by thousands, and by the fact that the plant also spreads by underground rhizomes, and you can see why some regard oriental bittersweet as a dangerous beauty.

A Better Option
American bittersweet (Celastrus scandens) also sports attractive yellow and red berries, yet it isn't nearly as invasive as its oriental cousin. Native to central and eastern North America, American bittersweet is a protected species in some areas, having become scarce due to overharvesting and competition from its invasive cousin. There is also some concern that American and oriental bittersweet can interbreed, damaging the purity of the native species. The two varieties are similar in appearance. However, American bittersweet's fruits are always found in clusters at the ends of stems, while Asiatic bittersweet's fruits are found in the joints where the leaves grow out of the stems.

Growing Bittersweet
If you decide to grow your own decorative American bittersweet, there are two things you should know:

1. The plant is dioecious, meaning that there are male and female plants and you'll need both to get berries on the female plant.

2. The plant has an rangy, unkempt look with little landscape value except for the fruiting branches in fall. Plant it in an out-of-the way area.

Avoid planting oriental bittersweet, even if it isn't expressly prohibited in your area. And if you purchase a decoration containing oriental bittersweet, take care not to let the fruits drop during transport. When you are finished with the decoration, dispose of it in the trash, not the compost pile or back woods.


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