Towards a unified model of Fallopia japonica (Japanese knotweed) growth and control by mechanical techniques

There is currently no control strategy that is effective at eradicating large stands of Fallopia japonica (Japanese Knotweed), despite much research on potential techniques for doing so. Mechanical control techniques have largely been written off as ineffective, largely owing to the impossibility of removing the below-ground rhizomous portion. However, Seiger and Merchant (1997) found that the cutting of above-ground biomass is sufficient to reduce below-ground biomass over time. The efficacy of this approach depends on the relationship between rhizome mass and annual regrowth of above ground biomass. Here, the impact of varying light and nutrient conditions on this effect is explored. Ultimately, initial rhizome mass is an important predictor of regrowth only in light- or nutrient-limited conditions. These results, along with results from the literature, are used to create a computer model of F. japonica growth, which suggests that combining removal of above-ground biomass with reseeding an area with native plants has the potential to lead to the eventual eradication of F. japonica from an area