GardenSMART :: Japanese Barberry is Invasive Plus Ticks Love It
Japanese Barberry is Invasive Plus Ticks Love It
By Therese Ciesinski, GardenSMART
You know Japanese barberry (Berberis thunbergii) as that ubiquitous landscape shrub: It's a specimen planting around houses, shopping malls, and gas stations around the country. It was introduced to the U.S. around 1875, and quickly became popular: it's easy to grow, with pretty spring flowers, great fall leaf color and brilliant red berries, plus it's deer resistant. It's also quite thorny, though to those looking to plant a barrier, that's in its favor.
What you may not know about Japanese barberry is that by the 1980s it had become invasive. Very invasive. Its berries are eaten, then excreted, by birds, and the plant sprouts and flourishes in woods, fields, and in wetlands, where it was never intended to be. It not only crowds out and overshadows native plants while hogging sunlight, water and nutrients, it changes the soil's chemistry, creating the environment it requires to flourish while making it harder for other plants to grow.
Japanese barberry is on the invasive species list of more than a dozen states, and is a problem in a number of our national parks and historic sites. There are even places in the U.S. where it is illegal to sell it. Yet despite efforts to bring more attention to the problem, the plant is still sold and planted all around the country.
If invasiveness alone wasn't a good enough reason not to plant Japanese barberry, here's another one: it is a favorite habitat for blacklegged ticks (Ixodes scapularis). These ticks, also known as deer ticks, carry Lyme disease, babesiosis, and granulocytic anaplasmosis, serious diseases that can do long-lasting damage to the body, and can even be life threatening.
For years, Agriculture and Natural Resource scientists at the University of Connecticut at Storrs have been studying the effects Japanese barberry has on the native landscape. Among other findings, they discovered that Lyme disease-carrying ticks prefer the humid environment the leafy, low-growing barberry creates. The numbers are startling: over 120 Lyme-infected ticks were found per acre where barberry runs wild, and 40 per acre where it is contained, compared to 10 infected ticks where there is no barberry.
These researchers are controlling the barberry – and thereby the ticks – by using propane torches to kill the plants. Though burning has to be repeated every five years as new barberry sprouts, they say it's still the easiest and most cost-effective way to get rid of large populations of plants.
So if you have a Japanese barberry in your landscape, dig it up! Don't just cut it back because it will send up shoots from the roots (it also roots along the stem where it touches the ground, like forsythia). Uproot the entire plant.
And if you don't have it, don't consider putting it in your landscape.
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