Many plants in our landscape are considered invasive. The most common ones are autumn olive, tree of heaven, multiflora rose and Japanese knotweed. Plants like these are species that have the ability to grow rapidly, flower and produce seeds rapidly and they produce abundant seed. They will grow in poor soils and in environments that other plants do not like.
Our official list in Pennsylvania contains 13 weeds that are considered "noxious." They are marijuana, Canadian thistle, multiflora rose, Johnson grass, mile-a-minute weed, kudzuvine, bull thistle, mush thistle, shattercane, jimson weed, purple loosestrife, giant hogweed and goats rue.
Other lists of invasive weeds can be much longer and include plants commonly in our landscape. These include Norway maple, Japanese barberry, burning bush and English ivy. Others will include garlic mustard, to name a few.
If you have these in your yard, you should get rid of them, especially if they are on the noxious weed list. Some, like autumn olive, can be dug up when small. On others, like multiflora rose, you will need to use an herbicide. Once you get rid of the bad plants, replace them with one of the native plants.