City of Madison Engineering Announces Management Plans to Continue Multi-Year Control Effort
The City of Madison Engineering Division has announced vegetation management plans for this fall that will follow-up on work done the earlier two years to contain, and eventually eradicate, infestations of Japanese knotweed from portions of the right-of-way bordering the South West Commuter Path. This blog has covered the Japanese knotweed story in several previous posts, click here for an overview of the Japanese knotweed problem, or click here for an example of how it has spread along the SW Bike Path.
“A contractor will be applying herbicide to Japanese knotweed during the week of August 24, 2015. This is a follow-up herbicide treatment to the 2014 treatment, which has proven to be very effective. The two sites being treated are 1) between Virginia Terrace and Glenway Street and 2) on the southwest side of Odana and SW bike path intersection (knotweed areas are approximate on images below). Signs will be posted to alert bike path users of this work”, said Carissa Wegner of the City of Madison Engineering Division in a notification.
Why Worry About Japanese knotweed?
Japanese knotweed (Fallopia japonica); also known previously as Polygonum cuspidatum, is a vigorous perennial plant that spreads through rhizomes and is adapted to growing along waterways and in poor, rubble-strewn soil. The reddish, hollow stems, about the size of your wrist, can grow up to 4″ per day and reach a height of 10 to 12 feet, or more. The stems grow with such force that they can push up through asphalt and does not respect property boundaries. An established clone can spread to cover many acres and will continue to do so unless contained.
There are a variety of mechanical, cultural, and chemical control methods that may be appropriate and effective, depending upon the size, location, and age of the clone. Click here to see an excellent pamphlet from UW Extension on current control measures. Prevention of spread through root fragments is, of course, the preferred method. For a long-established and extensive clone like the one along the SW Bike Path, herbicide application is probably the most practical control strategy.
Location of the patches to be eradicated
Working with City Parks and volunteer bike path stewards who plant and maintain gardens along the path, City Engineering has identified two main infestations that will be worked on this fall.
Provided the herbicide application is effective, and to fill the gap left by the soon-to-be-gone Japanese knotweed, City Engineering and path volunteers this fall will sow seeds of pioneering and aggressive native plants that will be able to compete with any future knotweed infestations.