Do you know the difference between an invasive species and a native
one? Because you should. The Pennsylvania Department
of Conservation and Natural Resources (PA-DCNR) defines an invasive
plant as a species that has become a weed pest. One that grows
aggressively, spreads and displaces other plants. This is a problem
not only for surrounding plant life, but for wild life that sustain
themselves on nature’s bounty as well. Take this example
from E.G. Rall, Jr., expert in native restoration. “There’s
an invasive shrub commonly known as burning bush because it gets
a deep red color in the fall. Gardeners find it attractive to plant.
But not only is it aggressive, it gets little berries that birds
love to eat. Now the bush is popping up in woodlands, because the
birds have spread it with their droppings,” he says.
And then there’s the mile-a-minute vine. “It grows so
fast, you can’t control it. It will just engulf a tree,” notes
Rall. There’s a reason it got its name - it can grow 6 inches
a day and more than 25 feet in one growing season. The list is endless. And
to further complicate matters, what’s native in Pennsylvania
can be invasive in Texas, like the eastern red cedars that are taking
over the prairies. “It’s a problem everywhere,” notes
Gregg Robertson, president of the Pennsylvania Landscape Nursery
Association.
So if you’re the average gardener, how do you identify what
plants are native and what plants are invasive? Rall suggests
asking the employee at your local garden center. They should
know if the plant is native or has invasive characteristics, such
as aggressiveness. Or you may want to research what to buy before you
go to your garden center (try searching invasive plants at the PA-DCNR’s
website - www.dcnr.state.pa.us for a list of moderate and serious threats).
If you’ve inherited a problem, don’t worry, steps can
be taken to restore the area. One way is to “manually
remove the plants. In some cases you will need to sterilize the soil
by using clear, plastic sheeting. The sheeting allows heat to build
up and kill the seeds. Sometimes it can take a month or more to kill
them,” says Rall. The other approach is by using chemicals,
which may or may not have various side effects depending upon what
you use and where you use it. Hiring an expert is often the
easiest (and best) route to go to insure the problem won’t
return.
And remember, when you’re at your local garden center sizing
up an invasive exotic whose colors fit perfectly into your gardening
scheme, there’s always a native alternative. Skip the burning
bush and go for a red chokeberry, instead. “It gets a
great fall color with similar habits,” says Rall.