Click below to listen to my Garden Bite radio show: Obnoxious weed of the month – Japanese barberry
There are plenty of noxious weeds, invasive species that move in on our native plants like boxelder bugs march into our homes as we approach cold weather! This month the Japanese Barberry is highlighted on the Minnesota Dept. of Agriculture’s list of OBnoxious weeds. But this bad boy isn’t just on Minnesota’s hitlist – it’s on the USDA’s too.
The photo above is from the Minnesota Dept. of Agriculture.
Japanese barberry is a 3- 6 foot tall shrub which is covered with sharp spines. Its small, round leaves are borne in clusters along the stem. Small, yellow flowers in summer turn to reddish-orange, oblong berries which dangle from the leaf nodes. The landscaping cultivars have highly variable leaf color including purple, green, gold, and lime-green. However, no matter their provenance, the escaped, naturalized plants will always have green leaves in summer which turn red or orange only in fall.
Japanese barberry was introduced to the U.S. as an ornamental. Since the 1980s, it has been found naturalizing in wooded areas. The shrubs will grow in full sun to deep shade. Deer won’t eat it due to its sharp spines, but birds will, thereby facilitating its spread. Barberries have the ability to change the soil chemistry beneath the plant, making the site more favorable for further infestation. Thanks to its ability to root from stems, Japanese barberry can form thick, impenetrable thickets.
Like a lot of invasive shrubs, it will hold onto its leaves in fall longer than native species. Management techniques include: Cutting, pulling, or digging small infestations. When disposing of plants, make sure the roots are exposed and dry out. You can also bag or burn the removed plants.