These plants are not yet considered invasive in Concord, but have the potential to become a problem. Keep an eye out for these plants to make sure that they don't become one.
Amur Cork Tree (Phellodendron Amurense)
Amur cork tree is a native tree to China, Japan, and Korea, and considered to be an invasive species in much of the Midwest as well as from Virginia to Massachusetts. It can be anywhere from 35-50 feet in height and is most notable for it's cork-like, ridged, bark for which it gets its name. The tree sports compound leaves and yellow-green flowers from May to June. Another distinctive quality is the grape like fruit it can produce after flowering. They are not to be confused with ash trees (Fraxinus) which also have compound leaves. With a high shade tolerance and an affinity for moist soil, this plant has the potential to move into wetlands and out-compete native trees and plants. A high amount of seed production, and a lack of natural predators, also allows it to reproduce in great numbers.
Japanese Stilt Grass (Microstegium Vimineum)
Japanese Stilt grass, as the name suggests, is an invasive grass native to Japan, Korea, and China. It was first recorded in the U.S. during the early 20th century in Tennessee. Since then it has spread all along the east coast. It is an annual grass that can eventually reach heights of 2 to 3 feet. Like many invasives, it does well in a wide variety of areas allowing it to out compete other native species. While it has not been recorded in Concord, it has been reported in Massachusetts so make sure to take note of it.
Kudzu (Pueraria Montana ssp. Lobata)
Kudzu is a perennial vine native to Asia that grows large blankets of leaves over trees and shrubs. Kudzu was introduced to the southern united states as a ground cover and erosion control plant in the 1880s. It has since spread like mad covering huge parts of the southern and Midwestern united states. The plant leaves consist of 3 small leaflets while the vine itself is woody and can reach 100 feet long. In mid-summer, the plant blooms with purple flowers. Most often kudzu reproduces by rhizome expansion, but seeds can also give rise to new plants. It is not yet considered invasive in Massachusetts, but there have been documented cases of it in Connecticut.
Mile-a-minute Vine (Persicaria perfoliata) Syn (Polygonum perfoliatum)
Mile-a-minute vine, similar to kudzu, is an Asiatic vine capable of climbing and strangling other plants. It features distinctive triangular shaped leaves, barbs, and dark blue fruit. Small white flowers bloom above the leaves around midsummer. It does well in environments from roadsides to wetlands. Mile-a-minute vine occurs from Virginia up to Massachusetts with cases of it reported on Cape Cod more recently.
Narrow-leaf Bittercress (Cardamine Impatiens)
Narrow-leaf bittercress is a flowering plant similar to garlic mustard in its reproductive cycle. The first year's growth will only consist of small rosettes while the second year it will flower and reproduce. The leaves are divided into small leaflets containing up to 11 on each leaf. A small bunch of white flowers blooms at the top. The seed pods, again similar to garlic mustard, form thin linear offshoots at the top of the plant once it has bloomed. The plant is self pollinating and can produce a vast amount of seeds. Bittercress has the ability to invade wetlands, flood planes, and meadows where it forms stands and out competes other plants. It is considered a weed in Massachusetts and should be watched for especially in swampy sections of land.
Rusty Willow or Gray Willow (Salix Cinerea & Salix Atrocinerea)
Rusty willow is a deciduous shrub, native to Europe, that can grow between 13 - 50 feet high. It has toothed leaves that are between 1 to 3.5 inches long. When pollen is produced in the summer, the plant gains a slightly yellowish tinge. Seeds are dispersed by wind is a cottony substance that sticks to leaves and grasses. This shrub does very well in wetlands and should be watched to make sure it doesn't invade ours.