Japanese Barberry is a deciduous, woody shrub in the barberry family (Berberidaceae). It has small, oval, spoon-shaped leaves with smooth edges that grow in an alternate arrangement along arching branches. These leaves are typically green and turn orange or red in the fall. Ornamental cultivars of Japanese Barberry may also feature burgundy or purple leaves. Its stems are erect and grooved, with a single needle-like spine at each node (where the stem produces leaves). New twigs are smooth, reddish, and become rough and grey as the plant grows.
In spring, Japanese Barberry produces small, six-petaled yellow flowers that grow in clusters of 2-4. Flowers produce red, oval-shaped berries that may persist into winter. Japanese Barberry resembles another invasive plant called Common Barberry (Berberis vulgaris). Common Barberry can be distinguished from Japanese Barberry by its three spines at each node and leaves with toothed edges.
Japanese Barberry grows in a wide variety of environments and can thrive in both full sun and dense shade. It is often found along forest edges, roadsides, stream banks, old fields, near trails, and residential areas. Once established, it forms dense, thorny thickets that are very difficult to remove and can make natural areas harder to walk through.
These thick patches crowd out native plants, decrease biodiversity, and can even alter the soil chemistry, making it more difficult for native species to grow. Research from Eastern USA indicates that dense thickets of Japanese Barberry create ideal conditions for Black-legged Ticks (which can carry Lyme disease) and increase the risk of tick encounters in areas where it grows.
Japanese Barberry is native to Japan and China and was introduced to North America in the late 1800s as an ornamental plant. It was initially marketed as a replacement for Common Barberry, which was found to host black stem rust disease, a disease affecting cereal grasses such as rye, oats, and barley. Japanese Barberry has now become a very popular ornamental species due to its bright berries, colourful foliage, and deer resistance.
Once planted, Japanese Barberry spreads through underground clonal shoots and the tips of its branches, which root when they touch the ground. The plant also produces berries that remain on the stems into winter and are eaten by birds and small mammals, dispersing the seeds to new areas.
Northern Bush-honeysuckle (Diervilla Ionicera) is a native shrub that thrives in sun and light shade. It has yellow flowers and foliage that emerges copper in the spring. Sweet-fern (Comptonia peregrina) is another native alternative with pleasantly scented foliage and supports native butterflies.
Oval leaves with smooth edges; arching stems with a single spine at each node; clusters of small yellow flowers; red oval fruit; variable foliage colour depending on cultivar.
Thickets of Japanese Barberry can change the soil’s pH, nitrogen levels, and microorganisms, making it more difficult for native plants to grow.
Promote the use of non-invasive shrubs in gardens and landscaping. Remove new infestations promptly to lower management costs. Due to its shallow roots, digging or pulling can effectively control Japanese Barberry. Refer to the Japanese Barberry Best Management Practices document for management options. Thoroughly clean all tools and clothing after contact with infested sites to prevent spreading.
If you spot Japanese Barberry, report it on iNaturalist or directly to the NSISC. Reporting helps track and manage the spread of this invasive species.