Common Name: Japanese Barberry
Scientific Name: Berberis thunbergii DC
Japanese barberry is a specially regulated plant, with a three year production phase-out of the 25 seediest cultivars beginning in 2015 (see list below). These cultivars average greater than 600 seeds per plant. After the phase-out period, beginning January 1, 2018, these cultivars will become Restricted Noxious Weeds in Minnesota and will be illegal to sell and propagate. Minnesota Noxious Weed Law.
Japanese barberry was introduced to North America in the 1800s as a popular ornamental and landscape plant. Grown for its interesting foliage colors, deer resistance and adaptability to urban growing conditions, Japanese barberry has been discovered naturalizing in understory wooded areas in Minnesota.
Japanese barberry is adapted to many soil types and can grow in full sun to shade. In Minnesota it has been found naturalizing in wooded areas, forming large, impenetrable thickets.
Japanese barberry seeds are spread by birds; plants also spread vegetatively by low branches that will root when they come in contact with soil. It is also spread through intentional ornamental and landscaping plantings. View Japanese barberry distribution in Minnesota.
Japanese barberry infestations cause many detrimental ecological and economic impacts. It has the unique ability to change the chemistry of the soil beneath the plant, which in turn makes the site more favorable for additional Japanese barberry plants. Over time, the change in soil pH and the higher nutrient levels can contribute to changes in the whole ecosystem of the area, resulting in a decrease of native plant and animal biodiversity. Because deer do not browse on Japanese barberry, they will also contribute to native species decline in infested areas by feeding on the easier-to-eat native plants in the area. The dense stands of Japanese barberry effectively become a monoculture, replacing the diverse, native understory with one species. Japanese barberry invasion reduces the carrying capacity of wooded pasture and limits the movement of livestock. Cattle and other large animals cannot move through the thorny thickets.
Dense stands of naturalized Japanese barberry could result in public health concerns as well. Research in Connecticut and Maine showed that black-legged ticks were twice as numerous in Japanese barberry infestations as in non-invaded areas. Dense Japanese barberry growth creates a microclimate with the ideal humid conditions that ticks prefer. As the carriers of the bacteria that cause Lyme disease, increased tick populations could lead to more cases of Lyme and other tick-borne diseases in humans, pets, and livestock.
MDA Noxious Weed Program
County Ag Inspectors
Minnesota Department of Agriculture (MDA), 625 Robert Street N, St. Paul, MN 55155-2538, firstname.lastname@example.org