Invasive species

Invasive species: Asian Knotweed

Invasive species, and Asian knotweed in particular, are an increasing problem in nature areas, verges, parks and gardens. Asian knotweed is very hard to control, and increasingly displaces native species. It is also detrimental for infrastructure such as road surfaces, dykes, foundations and sewage systems.

Practical studies and advice on invasive species

Probos has a history of studying the effects and control methods of invasive species. For example, we have carried out studies concerning red oak (Quercus rubra), black cherry (Prunus Serotina) and northern highbush blueberry (Vaccinium corymbosum). In 2011 we published a practical guide on how to control invasive plant species (in Dutch).

Knotweed control

The most extensive study dealt with knotweed control. Between 2013 and 2016, Probos carried out a practical study, testing several methods to control Asian knotweed, for example intensive mowing, grazing, covering and herbicide treatment. In 2018 we started a number of field tests with other methods, such as treatment with hot water or steam.

Probos developed a decision tree helping landowners and managers to select the most suitable method for specific knotweed locations and is currently working on a national knotweed control protocol.

We set up and maintain a Dutch website on the controlling of Asian knotweed www.bestrijdingduizendknoop.nl. Next to this we host the website of the European Knotweed Control Network www.knotweedcontrolnetwork.eu. Probos seeks opportunities to share its practical experience with knotweed control and the control of other invasive species abroad and is open to join cross-border projects.