|
|
|
Japanese barberry and European barberry
NATIVE RANGE:
Japan and Europe
Flowering occurs from mid-April to May in the northeastern U.S. Pale yellow flowers about ¼ in (0.6 cm) across hang in umbrella-shaped clusters of 2-4 flowers each along the length of the stem. The fruits are bright red berries about 1/3 in (1 cm) long that are borne on narrow stalks. They mature during late summer and fall and persist through the winter.
European barberry (B. vulgaris) differs from Japanese barberry by its sharply toothed leaf margins and 3-pronged spines. European barberry is a glabrous shrub that can reach 3m (10ft.) in height. The habit of this plant is upright and arching. The branches are grooved and gray and usually have groupings of three spines (can be as few as one) along them. The spines are usually rounded, but can be rarely flattened. The dull green leaves are obovate to obovate-oblong and have finely serrate margins (occasionally the serrations are more prominent). The leaves are alternate. The bright yellow flowers of European barberry have an unpleasant smell. These flowers usually appear from late May into June. The fruit are ellipsoid in shape, red in color and are around 1cm (0.4in) long. They contain 1-3 small, black seeds.
ECOLOGICAL THREAT: Japanese barberry forms dense stands in natural habitats including canopy forests, open woodlands, wetlands, pastures, and meadows and alters soil pH, nitrogen levels, and biological activity in the soil. Once established, barberry displaces native plants and reduces wildlife habitat and forage. White-tailed deer apparently avoid browsing barberry, preferring to feed on native plants, giving barberry a competitive advantage. In New Jersey, Japanese barberry has been found to raise soil pH (i.e., make it more basic) and reduce the depth of the litter layer in forests.
Though European barberry is not very common on the landscape in most places, there is a risk that it could once again become a serious pest. The fact that it is an alternate host for wheat rust prevents its sale (seeds and plants) in many states. DISTRIBUTION IN THE UNITED STATES: Japanese barberry has been reported to be invasive in twenty states (CT, DE, IN, KY, MA, MD, ME, MO, NC, NH, NJ, NY, OH, PA, RI, TN, VA, VT, WI, WV) and the District of Columbia. Due to its ornamental interest, barberry is still widely propagated and sold by nurseries for landscaping purposes in many parts of the U.S. European barberry has been reported for states in the northern half of the country and south to Colorado, Missouri and North Carolina. It is present in all of the states of New England. HABITAT IN THE UNITED STATES: Barberry is shade tolerant, drought resistant, and adaptable to a variety of open and wooded habitats, wetlands and disturbed areas. It prefers to grow in full sun to part shade but will flower and fruit even in heavy shade. BACKGROUND: Japanese barberry was introduced to the U.S. and New England as an ornamental plant in 1875 in the form of seeds sent from Russia to the Arnold Arboretum in Boston, Massachusetts. In 1896, barberry shrubs grown from these seeds were planted at the New York Botanic Garden. Japanese barberry was later promoted as a substitute for common barberry (Berberis vulgaris) which was planted by settlers for hedgerows, dye and jam, and later found to be a host for the black stem grain rust (Puccinia graminis). Because Japanese barberry has been cultivated for ornamental purposes for many years, a number of cultivars exist. BIOLOGY & SPREAD: Japanese and European barberry spread by seed and by vegetative expansion. Barberry produces large numbers of seeds which have a high germination rate, estimated as high as 90%. Barberry seed is transported to new locations with the help of birds (e.g., turkey and ruffed grouse) and small mammals which eat it. Birds frequently disperse seed while perched on powerlines or on trees at forest edges. Vegetative spread is through branches touching the ground that can root to form new plants and root fragments remaining in the soil that can sprout to form new plants. ALTERNATIVE PLANTS: Many attractive native shrubs are available that make great substitutes for Japanese barberry. A few examples include bayberry (Myrica pensylvanica), ink-berry (Ilex glabra), winterberry (Ilex verticillata), arrow-wood (Viburnum dentatum), mountain laurel (Kalmia latifolia), ninebark (Physocarpus opulifolius) and hearts-a-bustin' (Euonymus americana). Please check with your state native plant nursery for suggestions for plants appropriate to your area. AUTHORS: Jil M. Swearingen, U.S. National Park Service, Washington, DC. (PCA-APWG WGG Fact Sheet) REVIEWERS: Sylvan Kaufman, Conservation Curator, Adkins Arboretum, Ridgely, MD. For more information
on Japanese and European barberry, please contact: REFERENCES:
Plant Conservation Alliance, Alien Plant Working Group. |
||||||||||||
