Japanese knotweed spreads with lightning speed. It is considered as one of the most invasive exotic species for good reason. Due to its strong growth it displaces native plant species and its strong rhizomes and stems can cause damage to buildings, pipelines and roads. Once established, the plant is difficult to remove. Japanese knotweed can grow up to 4 metres tall and has stems that are hollow inside and composed of compartments. The plant has large heart-shaped leaves and flowers in August and September with creamy white flowers. This plant is native to Japan, China, Taiwan and Korea. The plant has become naturalised quickly in recent decades, probably due to the dumping of garden waste. Japanese knotweed is not very common in the dunes.