TRAVERSE CITY, MI – There are two widely popular landscaping shrubs wreaking havoc on forests across Michigan and the Midwest: Japanese barberry and winged burning bush.
The bushes are known to explode into shades of oranges, reds, and purples during the autumn, which is why the species remain popular choices within home and business landscaping designs.
The worse of the two in Michigan – at least so far – is Japanese barberry, but environmental experts say winged-burning bush remains poised to become just as problematic. Birds eat berries from the shrubs both species produce, then leave behind the seeds in droppings across the landscape.
The invasive plants then take root in other places, able to spread far and wide seemingly without ever jumping out of hedgerows or landscaping, but that’s simply not the case. It’s a type of spreading invasion many landscapers and home gardeners never notice.
“We are seeing our forests start to fill up with barberries, especially near where people have them planted. So, a lot of times you’re not seeing these barberries growing in your yard, you’re seeing them in the forest, and then that can impact our health as well as of course the function of our ecosystem,” said Katie Grzesiak, terrestrial invasive species coordinator for the Michigan Department of Natural Resources.
Japanese barberry shrubs now grow wild across Michigan, with heavy infestations in places such as Clinton and Manistee counties.
“We’ve been growing this plant in our landscapes for a really long time, but birds have been eating those berries the whole time we’ve been here. Birds don’t stay in one place, and they love to fly out into other areas, whether it’s your neighbor’s yard, or a local park or a local forest. And they release those seeds through their digestive system – the preferred dispersal method of Japanese barberry,” Grzesiak said.
“At that point, Japanese barberry is able to sprout and it’s especially good at spreading in the understory in a forest. So, areas that are kind of shady, maybe a little bit moist, and those little seedlings are able to grow and flourish in these environments.”
Maps of infestations of both the invasive barberry and burning bush can be viewed online through the Midwest Invasive Species Information Network.
Grzesiak said deer don’t like the taste of either Japanese barberry or winged-burning bush, so the invasive shrubs can grow unchecked. That leads to a monoculture of the bushes that not only drives away the wild deer herd, but the loss of biodiversity can also disrupt the ecosystem’s food chain, she said.
However, the big risk to human health comes with infestations of Japanese barberry bushes, which have accompanying outbreaks of a particular type of parasitic tick.
“One of the few critters that really likes Japanese barberry habitat is the black-legged tick, which is the tick that carries Lyme disease. And although that tick is native to Michigan, you know Lyme disease is a big problem for human health and areas with heavy monoculture of barberry have about 12 times as many ticks as does a regular non-barberry forest,” Grzesiak said.
Winged-burning bushes don’t seem to bring the same inundation of parasitic ticks, she said.
Related: Invasive silver carp genetic material found in Michigan river
Michigan does not regulate the sale of either Japanese barberry or winged-burning bush, though other Midwestern states do.
Minnesota, New York, and Wisconsin all prohibit the sale of Japanese barberrythough they exclude certain cultivar varieties. Indiana banned all varieties of the Japanese barberry.
For the winged-burning bushsales were phased out by the beginning of this year in Minnesota. Sale of winged-burning bush is also prohibited in Wisconsin, save certain cultivar varieties, and sales are allowed in New York but require labeling as invasive species.
“Michigan does have a law in place that allows for regulation of plants, but these have not yet been placed under that law,” Grzesiak said. “Those are species that could be listed in at a future time but there is not yet a completed weed risk assessment for either species.”
Conservation expert Shelly Stusick said there are a number of native plant species that can be used instead of Japanese barberry and winged-burning bush, especially if attractive autumn color is what landscapers and home gardeners desire.
Native plant options that are better for the ecosystem include ninebark, New Jersey tea, shrubby St. Johns-wort, black chokeberry, winterberry holly, and fragrant sumac.
It’s important to consider the environment when choosing species to replace Japanese barberry or winged-burning bush in landscaping, Stusick said.
“For instance, I’ve seen (Japanese barberry) in wet and shady woodlands but also in spots where the soil is super dry and it gets blasted by the sun,” she said.
Stusick said the gardening idiom “right plant, right place” comes into play, meaning not every species is interchangeable and success depends on location. She runs a program for the Grand Traverse Conservation District focused on encouraging native plant use instead of harmful invasives, which is expected to eventually roll out statewide.
“However, you don’t need to replace Japanese barberry with a shrub, per se. Grasses, trees, or wildflowers are also great options for folks who want to switch things up,” she said.
The best time of the year to remove or treat Japanese barberry is from June through November.
“If landowners are interested in removing barberry they may have on their property, small bushes can be dug up, while larger bushes can either receive a cut-stump treatment or by using a weed wrench to help remove the bush from the ground,” said Audrey Menninga, coordinator for the Northwest Michigan Invasive Species Network.
More environment news
2023-09-26 11:15:00
#Invasive #Japanese #barberry #burning #bushes #harming #Michigan #forests
