144546 APANESE KNOTWEED Fallopia japonica (Polygonaceae) Height to 2m. Fast-growing and invasive perennial, quick to colonise roadsides and other wayside places; hard to eradicate. FLOWERS are whitish and borne in loose, pendulous spikes that arise from leaf bases (Aug-Oct). FRUITS are papery. LEAVES are large, triangular and borne on red, zigzag stems.