Invasive Plants or Trees

Read about some of the changes to the Woodland Stewardship Education program and News and Notes about stories you might have missed. Our regular features include the Woodland Wildlife Spotlight and Invasives in Your Woodland, and the Brain Tickler challenge. 

In this issue, we look at musk thistle, also known as "nodding thistle," one of four invasive thistles classified as a noxious weed by the Maryland Department of Agriculture. Each plant can spread over 100,000 seeds.

Since its debut as a regular Branching Out feature in 2016, "Invasives in Your Woodland" has profiled a wide variety of invasive plant species that threated the health of Maryland's ecosystems.

Afforestation is the process of planting trees in formerly open space. Because trees take time to mature, it is important to ensure that the seedlings have sufficient light and nutrients to grow. This often involves controlling growth of other species within the planting area, including invasive species such as the distinctive Johnsongrass. And once established in an area, Johnsongrass can out-compete many other species for nutrients and over-top them to rob them of sunlight.

Canada Thistle is also known as creeping thistle, as well as green or perennial thistle, depending on the source. Others express their opinion about it by calling it hard thistle and cursed thistle. Canada thistle is an aggressive and colonial perennial, with both male and female plants. It is considered a noxious weed in Maryland and many other areas across the U.S.

Japanese privets are less common than other privets that are more widespread across the eastern U.S. Reported sightings in the mid-Atlantic are sparse, but it may be more widespread, based on its continued use in landscaping.

Winged euonymus is not widespread in the mid-Atlantic. Its greatest reported infestations are in the Midwest and Northeast. It has been found in much of central and southern Pennsylvania, far northern Delaware, southwestern Virginia, north-central West Virginia, and the greater Washington DC area.

European buckthorn is a native of Europe and was introduced here as an ornamental plant, perhaps as early as the late 1700s. In the 1900s, it was planted widely to form living fence rows and for wildlife habitat. Since then, it has spread aggressively into a variety of environments.

Mile-a-minute is a vigorous invasive that may only have just begun to spread in the United States. One estimate surmises that it is only found in 20% of its potential range in this country.