Barberry

Japanese barberry. Photo: Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Japanese barberry, or Berberis thunbergii, an invasive but popular landscaping shrub due to its red color and deer resistance, will be illegal to sell or cultivate in Pennsylvania by Fall 2023. The PA Department of Agriculture added Japanese barberry to a list of noxious weeds — plants that cannot be legally sold or cultivated in the state—last month. The non-native, ornamental shrub forms dense, prickly thickets and has increasingly garnered attention in the past several years as a prolific invader that can easily spread into woodlands, pastures, fields and natural areas, crowding out plants and disrupting native ecosystems. It is also thought to harbor black-legged ticks that spread lyme disease. The ban on sale and cultivation took effect October 8, 2021.

Pennsylvania now joins other northeastern states, such as New York, Maryland, and others, that ban or restrict the sale of Japanese barberry. In Maryland, for instance, the Department of Agriculture (MDA) has named it a Tier 2 invasive plant. This classification means retail stores  must display a sign indicating it’s an invasive plant and landscapers may not supply it unless they provide their client with a list of Tier 2 invasive plants.

Enforcement of the ban in PA will be phased in over two years to allow time for nurseries to eliminate it from their stock, find non-harmful alternatives, and develop seedless, sterile varieties that pose less threat to the environment and agriculture. Landscape and nursery businesses will receive notices of the timeline, procedures, and exemption process for sterile varieties. Property owners should consider eliminating the shrubs on their land.

Japanese barberry was originally brought to the U.S. from Japan and eastern Asia in the 1800s to be planted as an ornamental. “Many seemingly attractive plants can actually harm our environment, our food supply and our health,” said Agriculture Secretary Russell Redding. “Pennsylvania does not take banning the sale of a plant lightly. Prevention is the best alternative — choosing native plants that harbor pollinators and allow a healthy, natural ecosystem. Carefully considering the potential impact of what we plant can prevent lasting damage that is difficult, expensive or impossible to reverse.”

The timeline for the two-year rollout of the ban is as follows:

  • November 2021 – Nursery and landscape businesses will receive notice from the department, advising them to immediately begin adjusting propagation, ordering and planting of Japanese barberry to decrease inventory.
  • Fall 2022 – The department will issue letters of warning to any plant merchant still selling Japanese barberry, providing a date in Fall 2023 after which remaining inventory will be subject to a destruction order.
  • Fall 2023 – The department will issue Stop Sale and destruction orders to plant merchants selling or distributing Japanese barberry.

The department also added two other plants to the noxious weed list: garlic mustard, Alliaria petiolata, and Japanese stiltgrass, Microstegium vimineum. While these plants are generally not sold in nurseries, property owners with these plants on their land are encouraged to remove them. Find more information about noxious, controlled and poisonous plants in Pennsylvania at agriculture.pa.gov.