Ahh ... the lovely season of spring. A time of newly green leaves and emerging buds. A time to go outside and enjoy the fresh, warm air. A time to take up the annual war against invasive plants.
Not to spoil the pristine beauty of spring, but if you want to win the battle against your chosen nemesis, be it honeysuckle, garlic mustard or purple loosestrife, the time to start is now.
Throughout the Northland, many beautiful plants are now beginning to grow and bloom. Many are native to the region, but quite a few of the plants in your backyard are exotic. Some are invasive, but most are not.
Often, the term "invasive species" is used interchangeably with non-native or exotic species. But native species can also be invasive, while non-native species may not.
Take the beloved dandelion, for example. It is not native to Wisconsin (it was introduced by European settlers), but it is not considered an invasive plant. That doesn't mean it won't take over a lawn if given the chance. It simply means in the state's natural (uncultivated) landscape, dandelion coexist with native plants, rather than out-compete and replace them. Invasive species, on the other hand, crowd out native plants and cause damage to the ecosystem.
ADVERTISEMENT
Many of the most troublesome invasive species are now common knowledge. Purple loosestrife, which often blankets ditches near highways, is one invader almost everyone has heard of. But other species have not received as much attention, although they are no less destructive.
Invasive species to be aware of include: common buckthorn, showy bush honeysuckle (as well as other varieties of exotic honeysuckle) black locust, multiflora rose, Japanese knotweed, dame's rocket, black swallow-wort, Japanese hedge-parsley, birdsfoot trefoil, and common tansy.
A few well-publicized invasive plants are wreaking havoc in other parts Wisconsin but have yet to advance to the northern region of the state. Garlic mustard is a prime example of this. In many state parks and recreational areas of southern and eastern Wisconsin, volunteers put on their glove and head out in droves to pull garlic mustard every spring. As of 2006, garlic mustard was still absent from the Brule River State Forest, but people have reported sighting the plant throughout the state.
The key to beating invasive plants is to start early, before they become well established. Wether you use chemical means or mechanical (pulling or digging up plants or cutting them), you will be most successful if you begin when the plants are just beginning to sprout in the spring.
Not an option to control invasive species: burning the plants. Prescribed burns are often used to manage native ecosystems, but fire danger is still too high to consider any sort of burn at this time. Even in the best condition, some risk is always involved in a prescribed burn.
Some species of terrestrial plant may have become such a fixture around your home, you may not be aware they are invasive. In fact, most of the plants probably wouldn't draw your attention ... until you look around and see just one plant were a variety used to be.
Because invasive plants can take over so quickly, one of the best things you can do to keep them from spreading into your backyard is it to be aware of which plants are invasive or have the potential to be invasive. Three sites to check that list the most common invasive plants in Wisconsin or Minnesota are www.ipaw.org , www.dnr.wi.gov/invasives , and http://www.dnr.state.mn.us/invasives/terrestrialplants .
Also, talk to local garden clubs about native, non-invasive alternatives when planning or planting your garden. Many gardeners inadvertently introduce invasive plants to their area without knowing it. None of the plants pictured on this page are invasive, so they may be a good start to a flower garden.
