Revaluing Japanese Knotweed as a Circular Resource

Japanese knotweed grows and spreads rapidly, smothering native plants in the process. It’s also notoriously difficult to eradicate, with existing methods including the use of environmentally damaging chemical weedkillers and incineration. But four Rotterdam-based companies are hoping to help mitigate these negative effects by establishing a localised economic supply chain.

Using waste streams generated by landowners and national organisations (such as water and rail boards), green contractor GKB Groep has devised various methods for safely processing the knotweed into chippings, ready to be experimented with by the other project members.

Papermaker Chayka will extract lignin for use in its production, while plant specialist Dubbel Doel Flora will investigate fibres as an alternative to peat in potting soil. Having already developed a biodegradable sheet material similar to OSB (which can be shredded and then repurposed), design studio Why Knot is working to improve its properties, alongside exploring new product avenues, such as paint and shampoo.

After 18 months of trials, the consortium hopes to be able to roll out a successful circular chain. Localised and national partnerships like this are becoming instrumental in tackling problematic waste streams, and brands should consider forging relationships with third parties to help establish innovative upcycling solutions.