Invasive plant thrives in Schuylkill County
It kills trees and bushes but invites spiders, snakes and frogs.
It grows rapidly and is not easily killed as it ruins sidewalks, roads and foundations.
As Japanese knotweed continues its conquest of North America, it's hard to take a stroll along Schuylkill County's many walking paths without spotting the tall, bamboo-like weed.
"It's completely taken over the path over there," Sara Saurazas, 19, said Wednesday, walking a pair of dogs along the City of Pottsville Bike Path and Jogging Area near the JFK Swimming Pool. "I'm kind of scared. I don't want there to be snakes in there. I don't want them to get bitten."
Commonly called "fleeceflower," "huzhang" or "monsterweed" according to Patrick M. "Porcupine Pat" McKinney, educational coordinator for the Schuylkill Conservation District, Japanese knotweed has been in the county for decades. However, it is only in recent years that officials have gotten a handle on controlling the robust plant.
"It would have to be a battle to keep that plant at bay," McKinney said.
A closer look
Found in waste spots, like along roadsides and stream banks, Japanese knotweed can grow in almost any type of soil. The invasive species can damage foundations, buildings and flood defenses, as well as lift and crack blacktop roads and concrete.
The only known predator of knotweed is the insect aphalara itadori, a Japanese psyllid recently used in the United Kingdom to help control the growth of the plant.
Japanese knotweed was introduced to North America in the late 19th century for use in ornamental hedges and for erosion control. It is believed that the knotweed was introduced to Schuylkill County in the early 20th century to help re-vegetate areas cleared for mining.
Controlling the plant proved difficult, however, because the plant grows back quickly after being cut. Digging up the plant is a less-used option because the roots of the plant may extend laterally from seven to 20 meters, and the entire plant must be removed.
Keeping knotweed from spreading proves even more difficult than just cutting it down or spraying it with herbicide. The plant's seeds can be dispersed by wind, water, birds and insects into the water, float to a new site, begin the process over, and spread farther and farther downstream each year. Knotweed also spreads through rhizomes - underground stems that send out roots and shoots from its nodes. Rhizomes are very durable and can survive for decades.
Much of the local knotweed is found along the Schuylkill River and its tributaries throughout the county. It has killed off plants and trees that should be in the river area, such as spice bush, a wet woodland shrub with twigs that emit a spicy fragrance when scraped, along with American sycamore, river birch and hemlock. Although it strangles any vegetation in the area, the knotweed is not harmful to animals or humans.
"We've had limited success. You never seem to quite get ahead of it." Scott Graver, Schuylkill Haven borough administrator, said about the efforts put forth at The Island to control the plant. Methods used at The Island, as well as throughout the county, include cutting it and spraying herbicides, such as Roundup.
"We cut it down, leave it sprout until it gets to be about one-third its height and then we spray it with Roundup," Frank P. Snyder, service forester for Carbon and Schuylkill counties, said during a phone interview. "In most cases, we're trying to eliminate it and replace it with native species."
"We've been battling this for years throughout the county," Thomas A. Palamar, administrator of the City of Pottsville, said during a phone interview.
Pottsville entered into a contract with Ehrlich Pest Control a few years ago and works with the company to control the spread of the plant.
"We have tried so many different things and we have found that working with a professional has worked best," Palamar said. "It's safer and more cost-effective to work with them."
Daniel E. Kelly, superintendent of streets and parks for Pottsville, said that working with Ehrlich has eliminated a lot of cutting, because the plant must be cut two to three times a season.
"It still grows but at a slower rate. It takes a few years of treating it to totally eliminate it," Kelly said.
Not all bad
Although an invasive and destructive species, there are some uses for knotweed. If it is under 6 inches tall, it can be eaten raw, although cooking it is usually recommended. If it is between 6 and 12 inches, it must be peeled first and it tastes similar to rhubarb.
Medicinal uses have also been discovered for knotweed. Master herbalist Stephen H. Buhner, in his book "Healing Lyme," said the plant is effective for treating and preventing Lyme disease. Its anti-inflammatory qualities help the immune system combat various infections, relieves symptoms of arthritis and can protect the body against neurotoxin damage. It can also be used as a laxative or diuretic.
New studies have suggested that it may also delay the onset of Alzheimer's disease or slow its progression. Studies conducted at the Feinstein Institute of Medical Research, Manhasset, N.Y., have observed that the intake of the concentration of resveratrol found in knotweed has beneficial properties against the neurodegenerative processes that lead to the disease.
Although some benefits have been found, they do not eliminate the damage that can be caused if the weed continues to spread.
"It's definitely one of those invasive species that need to be controlled." Snyder said. "You need to stay committed to it and keep on top of it."