Invasive Plants You May Recognize
Simply put, invasive means "out-of-control". Invasives are immigrant species brought from an outside ecosystem or environment. In its natural environment, there are natural factors or enemies that maintain the growth or spreading of any species. When that species is introduced to a new environment or ecosystem, there is likely no natural control features. Allowing the species (plant or animal) to take over an area with little effort.
Some more commonly known invasives would include; Zebra Mussels (Dreissena polymorpha), Purple Loosestrife (Lythrum Salicaria), and Giant Hogweed (Heracleum mantegazzianum)
Urban invasives are very common. They are plants that most garden centers will have available for purchase but are difficult to control once planted. Most gardens contain invasives without even knowing it.
Lily-of-the-valley (Convallaria majalis) is an urban invasive plant. It does very well in our zone (Zone 3 - 4 CDN) but can be difficult to keep in an isolated area. Lily-of-the-valley prefers shaded areas and is a tuberous plant. This plant is also poisonous but when dried, is used in herbal remedies.
If Lily-of-the-valley is one of your favorites, make sure to maintain the planted area and remove access plants to prevent unwanted spreading.
Periwinkle (Vinca minor) is a beautiful perennial vine. Shade loving and can grow anywhere. Even with its deep green foliage and range of available colored flowers, it is still very invasive. Able to grow several metres per year, this plant can quickly become out of control.
The best control method for periwinkle is continuous maintenance throughout the growing season. There are no special pruning techniques required. Just grab the vine and cut. You can cut it back safely to 6" from the main root.
Bishops Goutweed aka Bishop Weed, Snow-on-the-mountain (Aegopodium podagraria variegatum) is usually recommended as a ground cover for hard to grow areas. It works great! So great that your whole garden will be covered with it in no time. This invasive reproduces by seed that can be carried in the wind and by rhizomes (spreading, underground roots that send new stokes up).
This plant is deer and rabbit resistant. To prevent seeding, cut the flower heads off as soon as you notice them.
The best control is not planting it at all. If your garden does contain this hostile plant, some sprays may be effective but you're likely going to need to do some heavy digging to get all those roots and runners to completely remove it.