WHAT DOES JAPANESE KNOTWEED LOOK LIKE?

What does Japanese Knotweed look like? - http://www.wwcs-group.co.uk/

Despite its fearsome reputation, Japanese Knotweed - Fallopia japonica, is a surprisingly attractive ornamental herbaceous plant. It was first introduced to Europe by German botanist Philipp von Siebold (1796–1866) who obtained a specimen from a Japanese volcano and brought it to Holland.

Young Japanese Knotweed growth - http://www.wiseknotweed.com/

The Royal Botanic Gardens, Kew obtained a specimen in 1850, and once brought under cultivation became a gardener's favourite. Why? Because it looked like bamboo and grew in almost all soil types in both sun or shade. However it is the robust adaptability of Japanese Knotweed which has caused it to fall out of favour. It is now listed by the World Conservation Union as one of the world's worst invasive species!

Once mature, which is usually when they start to draw attention, Japanese Knotweed will achieve a height of approximately 2-4 m tall depending on conditions, and form dense stands. The hollow, bamboo-like stems are green, speckled purple, with distinct raised nodes.

Japanese Knotweed leaf and flower - http://warehouse1.indicia.org.uk/

The lush, green, broadly oval leaves are 7–14 cm long and 5–12 cm wide, and flattened at the base. They are borne alternately on characteristic zig-zag stems. The small blooms appear in late summer and early autumn. The flowers are cream or white and produced in erect racemes 6–15 cm long. While popular with pollinators, the seeds are rarely fertile.

Japanese Knotweed will naturally die back in early winter leaving the canes to turn brown. These canes will remain standing throughout the winter and while surprisingly brittle can be in place amongst the following spring and summer's new growth. New reddish-purple shoots appear in the spring from the ground which can grow up to an impressive, yet also worrying, 2cms a day.

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WHAT DOES JAPANESE KNOTWEED LOOK LIKE?
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