Invasive Species in our watershed

Japanese Knotweed

Spotted Lanternfly

One prominent invasive species is the Japanese Knotweed. This plant is native to Asia and was introduced into the U.S. during the 1800s. Knotweed currently grows abundantly all along the Lackawanna River.

See the Q & A section below for removal tips!

Spotted Lanternfly

The Spotted Lanternfly is a planthopper native to Southeast Asia and is currently making its way up to Scranton and the rest of our Watershed from southeast Pennsylvania. These exotic insects threaten agricultural commodities, which in turn can have a major impact on local economies. If you see this invasive species, please report the sighting to Penn State Extension

Photo & more info here

Emerald Ash Borer

Spotted Lanternfly

This beetle is native to regions in China, but has made its way into the Lackawanna River Watershed. This invasive species is harmful to our Ash trees because the larvae bore into the ash tree and feed under the bark. The feeding hinders the tree’s ability to transport water and nutrients causing the tree to die.

Photo & more info here.

Phragmites

Norway Maple

Phragmites is the genus of four species of large perennial grasses found in wetlands. Also known as common reed, these invasive species are aggressive perennial grasses that take over wetlands and out-compete native plants and displaces native animals.

Photo by Chesapeake Bay Program - Learn more Phragmite info here

Norway Maple

This invasive species was promoted as an urban shade/street tree in early 20th century. It does not get along well with Native species because it adds toxins to the soil with root tannin & these trees form in monocultures cluster and make dense shade making competition for light difficult for other species.

Photo & more info here

Ailanthus

Norway Maple

Also known as "Tree of Heaven", this invasive tree is from Northern China and is very common in urban America, including Scranton. When it is young, it can be confused with our native Sumac. It grows to be a large canopy tree 50 to 75 feet tall. A prolific seed producer, it also forms mono-cultural stands. It has a very smelly sap and its wood is useless for any uses. It is a common host to the spotted lantern fly!

Photo & Learn more here

Questions & Answers

What are invasive species?

A species is considered invasive when it is removed from its original habitat range to a new area where it then lacks predators. Invasive species are usually harmful and disruptive to the environment, the economy, or human health.

What impact do invasive plants have on the environment?

Invasive plants can take over habitats and force native species out due to fast reproduction in the Springtime. Invasive plants can also reduce native wildlife habitat which affects the food chain and can disrupt pollination in habitats. Invasive species can also lead to soil erosion, changes in water and nutrient availability. As you can see, there can be many ecological impacts!

What is the best way to remove Knotweed?

Knotweed has been controlled by herbicide application. Now that Glyphosphates, such as "Roundup," is known to be carcinogenic, traditional means, such as aggressive cutting, can work to control Knotweed. However, it can be very labor-intensive. Non-toxic herbicide alternatives using cleaning vinegar, "Dawn" dish detergent, and Epsom Salts can work. Recipes to try.
The best way to REMOVE Knotweed is to start in early spring with a clearing of the debris of the previous year's Knotweed growth. This clearing can be done manually with hand tools or mechanically with a backhoe or skid steer. If possible, controlled fire is preferred.
The object of this removal work is to expose root wads, or root knuckles, that emerge from the soil. These root knuckles should then be removed by excavation with spades, picks, and mat-axes, backhoes, or other machines. Removal of all large visible knuckles, wads, and running roots is recommended. After removal, the loosened soil should be raked to a depth of 24 to 36 inches and sifted to cull all possible remnants of root matter.
Following removal of as much of Knotweed root material as possible, the soil should be raked and amended to plant grass lawn. Mow regularly for several years, and any localized regrowth of this invasive species can be picked out with tools and the area seeded with lawn patch. If the area of Knotweed removal is intended for landscape beds for shrubs, or for a rain garden, the follow up to the removal would be: (1.) prepare the soil for shrub and herbaceous planting, (2.) mulch the balance of the soil bed, (3.) monitor bi-weekly for Knotweed emergence and control.