Japanese knotweed’s elegance belies the truth it has become the scourge of home owners. It develops at an astonishing rate, is near-impossible to get rid of and has damaged home value – cleaning countless numbers off residence values. Japanese knotweed, or Fallopia Japonica, was taken to the US from Asia in the mid-19C by German-born botanist Phillipp von Siebold who thought it was increasing on the edges of volcanoes.
Initially famous for its elegance and thought of as a beautiful landscaping material, and it was so recognized that in 1847 it was known as the “most exciting new decorative Plant of the year” by the Community of Farming at Utrecht in Netherlands. Fleshy red tinged shoots when it first smashes through the ground.
Japanese knotweed has hollow stems with distinct raised nodes that give it the appearance of bamboo, though it is not related. While stems may reach a maximum height of 3–4 m (9.8–13.1 ft) each growing season, it is typical to see much smaller plants in places where they sprout through cracks in the pavement or are repeatedly cut down. The leaves can be spade shaped or broad oval with a truncated base, 7–14 cm (2.8–5.5 in) long and 5–12 cm (2.0–4.7 in) broad, with an entire margin. The flowers are small, cream or white, produced in erect racemes 6–15 cm (2.4–5.9 in) long in late summer and early autumn. The blossoms of Japanese knotweed can attract bees when it blooms in the summer.