Barberry article continued


Though the exact effect on native flora is not determined, it could prove a great threat to native species. This threat is such that the plant is illegal for sale in Canada, and included on some banned lists in New England. Asiatic bittersweet causes major damage to native plants by girdling. Mechanical damage to trees and other plants is also caused by the additional weight on branches, causing them to break. The vigorous growth of the vine also shades other species. Another threat is the possibility of Asiatic bittersweet displacing American bittersweet (Celastrus scandens). American bittersweet does not exhibit this aggressive growth, but it can hybridize with Asiatic bittersweet, exacerbating the problem. Unfortunately, people often use Asiatic bittersweet for autumn wreaths and floral arrangements due to its colorful fruits, but when these arrangements are later discarded the fruits are dispersed and the threat continues to spread.

Control Methods
This plant has a substantial seedbank, and complete eradication may depend on repeating control methods for several years.

Cutting

Cut climbing or trailing vines as close to the root collar as possible. This technique is feasible on small populations, as a pre-treatment on large impenetrable sites, and in areas where herbicide cannot be used. Cutting will reduce seed production and strangulation of surrounding woody vegetation. Asiatic bittersweet will resprout unless cut so frequently that its root stock is exhausted. Treatment should begin early in the growing season and be repeated at 2-week intervals until autumn.

Grubbing
This method is appropriate for small initial populations or environmentally sensitive areas where herbicides cannot be used. Using a “pulaski” or similar digging tool, remove the entire plant, including all roots and runners. Juvenile plants can be hand-pulled depending on soil conditions and root development. Any portions of the root system not removed will potentially resprout. All plant parts — including mature fruit — should be bagged and disposed of in a trash dumpster to prevent reestablishment.

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