Posted: 10/05/2015 at 17:09
I know it will be hard, but the best time to tackle anything with weedkiller is when it has a good area of leaves.
With knotweed you can also tackle it in late summer/early autumn. Cut the stem near the root, just below a node and pour or inject weedkiller into the hollow stem. Any pharmacy will sell you a plastic syringe which makes it easier.