Background Beginning in June, 2020 Regreen Springfield will embark on an aggressive program to pilot test various methods for controlling invasive vegetation in Springfield. Initial efforts will focus on control of Japanese Knotweed, which has been found in locations across the city. This pilot program will utilize several methods to control the invasive plant, and will examine the efficacy, cost effectiveness and logistical efficiency of the eradication practices. Additionally, combining control methods on specific stands of the invasive vegetation will be used to gauge the effect of a multi-faceted control strategy. This is a simplified way of describing Integrated Vegetation Management (IVM). Regreen Springfield proposes to develop a pilot Japanese Knotweed (Polygonum cuspidatum) eradication program for public and private lands in Springfield. Japanese knotweed, sometimes also known as ‘bamboo’, is a tall-growing, hollow-stemmed, perennial herbaceous plant capable of forming dense monocultures on a wide range of site conditions, ranging from roadway edges and forested settings, to stream banks and and disturbed landscapes. Knotweed is not a true bamboo (a woody, evergreen grass), but is a relative of plants such as buckwheat, smartweed, and the Noxious Weed mile-a-minute vine. Japanese knotweed was introduced to the U.S. for use as ornamentals during the late 1800’s. However, due to their imposing height (6 to 10 ft), dense growth habit, aggressive spread, and seeming indifference to control methods, the knotweeds have become a pervasive weed in a number of settings, including in public parks, conservation lands and on private property. Control
Methods and Implementation Program Due to the difficulty of initially treating knotweed, and the persistence of its rhizomes, effective control requires a programmed approach that includes initial control operations and ongoing maintenance. The pilot program to be used in Springfield will utilize several methods to control the invasive pest, and will examine the efficacy, cost effectiveness and logistical efficiency of the eradication practices. Additionally, combining control methods on specific stands of the invasive vegetation will be used to gauge the effect of a multi-faceted control strategy. This is a simplified way of describing Integrated Vegetation Management (IVM). The following sections describe the different approaches that can be used – ideally used together in a pre-planned program, rather than repeated instances of ‘fire-fighting.’
Cutting in itself is not entirely effective, but when combined with other methods will be used to control growth. June 1st thru August will be a targeted date. Cutting too early can result in full regrowth, and too late can result in reduced chemical effectiveness. Mowing will be used when possible, but mechanical or hand trimmers will be used when mowing is not possible.
Herbicides will be used in multiple ways to control the knotweed in Springfield. Foliar applications will be sprayed on the plants, between July 1st and the first killing frost. Soil applications are slower, but still very effective. They are absorbed slowly and stay in the soil for more than a year. Stem injections will also be used, as a more targeted approach for the removal of the knotweed.