Japanese Barberry (Berberis thunbergii)

Invader Type: 
  • Plant

SPECIES UPDATE

04/09/13
Cooperative Weed Management Association assist communities with the identification and control of non-native invasive plants in the Upper White River watershed
02/27/12
Urgent Alert:
New Species Added to Vermont's Plant Quarantine Rule
02/02/12
Urgent Alert:
University of Connecticut Releases Excellent Videos on Barberry
application/pdf iconJapanese Barberry Control Methods: Reference Guide for Foresters and Professional Woodland Managers

Control

Mechanical Control: 

Hand pull: Any time of year when the ground is soft, especially after a rain, hand pull small plants by the base of the stem. Be sure to pull up the entire root system. Hang from a branch to  prevent re-rooting. For larger plants, use a Weed Wrench™. Continue to monitor the area every year for new seedlings.

Cut stump: Cut plants back in the fall or winter. Wrap a few layers of burlap or thick plastic over the stump and tie tightly with twine or rope. Check covered stumps periodically and cut back any new growth.

 

Chemical Control: 

Cut stump: Cut the plant 4 inches above the ground. Use a drip bottle to apply a 18-21% glyphosate solution to the stump within one hour of cutting. This is best done in late summer through winter when plants are transporting resources to their root systems.

Low volume foliar spray:  This method is used for dense populations and best left to a contractor. In the fall, when native plants are losing their leaves, spray a 2% glyphosate solution on the entire leaf surface of the plant. In order to avoid drift to native plants, spray only on calm days.

 

The University of Connecticut has released an excellent video series on barbbery. Chek them out and share with others. If you don't believe barberry can get this bad in Vermont, it can and it has in many places throughout the state.

Part 1: The Trouble with Barberry

Part 2: Controlling Barberry

Part 3: All About Lyme Disease

Photos

Photos: 

Description

Identification: 

Japanese Barberry is a shrub that can be identified by its spatula shaped leaves, red fruit, yellow flowers hanging below the stem, and a single spine at each leaf base.

Reproductive Strategy / Lifecycle: 

Reproduction is mainly by seed but it can root sprout and layer. Barberry produces a large number of seeds with high germination rates, estimated at up to 90%. Fruits mature from July to October and persist well into the winter. Fruit production varies with light level, but even under very low light levels (4% full sun) some seeds are produced. 

Dispersal: 

Barberry has a very steep seed dispersal curve—most seedlings are found under or adjacent to adults, but a small number may be found tens of meters from the nearest adult. Seeds are disseminated by birds, grouse, turkey and small mammals.

Habitat: 
Japanese and Common barberry can aggressively invade in diverse habitats, from wetlands to fields and pastures to upland forests, in both moist and dry soils. As birds carry barberry seeds, it is common to find plants concentrated along tree-lined roadsides and field edges where birds roost. They thrive in sunlight and are tolerant of shade, however common barberry seems to be less shade tolerant than Japanese barberry and is less likely to be found in an interior, closed-canopy forest. Plants growing in dense shade may flower and fruit less heavily than those in more open sites.
History: 
Introduced as an ornamental
Legal Status: 

As of 2010, The Vermont Invasive Exotic Plant Committee (VIEPC) has proposed its addition to the Vermont Quarantine Rule.

References: 

(c) J. Samanek State Phytosanitary Administration; (c) C. Black; (c)Dr. Livingston; (c) IPANE; (c) TNC Bershire program; (c) L. Mehrhoff University of Connecticut.

Threat

Ecological Threat: 
  • Japanese barberry can quickly colonize a forest. Birds and small mammals feast on the fruits and drop them, starting new populations. The plants also reproduce vegetatively. Individual stems reach toward the ground and  ‘layer,’ developing new plants.
  • It can grow so thickly in woodlands that few native shrub and tree seedlings or herbaceous plants survive.
  • Barberry infestations can lead to increases in rates of Lyme disease. Ticks like to hang out on the tips of shrubs, waiting for mammals to pass by. Mice populations — an alternate host for Lyme disease — thrive in the thorny Barberry stands.
  • Japanese barberry (Berberis thunbergii) is sold in different ornamental varieties such as ‘Aurea’ with gold leaves or ‘Crimson Pygmy’ with purple leaves. Though these cultivars look different from the green-leaved Japanese barberry that is found in forests, studies show that  these ornamental varieties are all capable of producing offspring with green leaves.