By Pamela Doan
When it comes to Berberis thunbergii or Japanese barberry, it’s personal for me. I enjoy hiking and it’s deeply unsettling to see it colonizing our natural environment. The woods surrounding my house are full of it, nothing else grows but a few other invasive plants like garlic mustard, stiltgrass and Japanese knotweed.
I’ve been on a mission to get it under control in my own yard where it was left to overrun the landscape by previous gardeners. I have already spent hundreds of dollars paying a contractor with a backhoe to come in and remove large patches in the yard. Given how much of it there is, it’s the only solution. It has to be ripped out by the roots and removed.
This tenacity and hardiness is one of the reasons people plant Japanese barberry. On the surface, it has quite a few advantages. It can be cut to the ground, grown in poor soil, and the deer will not eat it, which is a major consideration for many plant lovers in Philipstown. It will grow in sun or shade, likes our cold winters, and the leaves turn color in the fall. As a hedge, Japanese barberry creates a thorny, impenetrable barrier.
Sound good? Well, here’s the rest of the story. It isn’t native to our area so it doesn’t have anything to keep it in balance. It’s been reported as invasive in twenty states and its line of aggression runs straight down the Eastern seaboard. It’s been problematic in the U.S. since the 1970s when it started taking over pastures and roadsides, displacing native vegetation.
This bush has a unique way of crowding out other plants. It leafs out early in the spring, earlier than other plants, and craftily shades out anything else. It also alters the soil pH and can spread easily. When a stem touches the soil, it can take root, spreading quickly. Birds eat its berries and disperse its seeds, which have a 90 percent germination rate.
As if those traits don’t impress you as plant superpowers, its seeds can lay dormant on the soil for ten years and still be viable and any root left in the ground can re-grow. In our forests, Japanese barberry is creating monocultures where nothing else grows.
In Canada, Japanese barberry is banned from sale. Locally, you can find it in just about any landscape center with a tag cheerfully promoting the joy it will bring in your landscape. Curious about why a garden center would stock it, I contacted Sabellico Greenhouses and Florists in Hopewell Junction, a personal favorite. Sabellico grows many of their own plants in their onsite greenhouses and I trust them for good stock and information.
They list Japanese barberry on their website. Gail Morris, manager of the perennials department, talked about how they decide what to stock. “If a customer requests Japanese barberry, we’ll mention that we don’t usually stock it and offer alternatives. If a customer has a barberry bush that has died and they want to replace it, we may order a few, not a large quantity.” To their credit, Sabellico recommends alternatives. “Spirea is a great alternative to barberry, also weigela, boxwood and holly,” said Morris.
All of those are great alternatives and none of them cause the environmental problems that Japanese barberry does. The native American cranberry bush or viburnum trilobum is native to our area, flowers, has nice fall foliage, and berries that birds love. A little deer spray will protect it. Sabellico offers information and seeks to educate their customers through an email newsletter. “We keep track of invasive plants using New York state resources and the Cornell Cooperative Extension’s information. We’re trying to responsibly introduce customers to more native plants, too,” said Morris.
If you’re still not convinced of the risks of planting Japanese barberry, consider this last point. Studies have shown that it is a perfect habitat for ticks. Ticks need humidity and the canopy of Japanese barberry can provide 100 percent humidity for them. Mice also use the foliage for nesting. Voila! A Lyme disease incubator, right there in your yard.
While it’s encouraging to hear that a garden center carefully and consciously screens their stock for problematic plants, it’s clear that gardeners need to make responsible choices when buying plants. The USDA database lists whether a plant is considered a threat along with its risk level. A little research before introducing any new plants into the landscape can make all the difference.
Photos by P. Doan