Bohemica’

(Fallopia x bohemica)

‘Bohemica’ is a hybrid species (click here) formed by Japanese knotweed and Giant knotweed. Consequently, it is also known by the name Fallopia japonica var. japonica x Fallopia sachalinensis. For many years, ‘Bohemica’ went unrecognised as a separate species and was only formally classified in 1983. It is widely distributed, with both male and female plants recorded in the UK. It can be variable in habit and it is common to find ‘bohemica’ growing in close proximity to, or amongst, Japanese knotweed. Leaves are larger than Fallopia japonica, up to 25cm (10 inches) long and 18cm (7 inches) wide, growing in a heart shape. Leaves are usually longer than they are wide, pointed at the tip, slightly crinkled in appearance and darker green than japonica, with short white hairs (trichomes) growing on the veins on the underside – particularly in the early part of the growing season. Veins are usually reddish purple in immature leaves. Growing habit, including stem colour and shape, is extremely similar to japonica. ‘Bohemica’ grows, on average, to a height of 2.5m-3m (8-10 feet), though taller plants up to 4m (13 feet) have been recorded. Rhizomes have a less prominent colour internally than japonica and can be bleached out completely to white. An absence of crowns has been noted during excavations. Creamy-white flowers appear in dense clusters in late summer/early autumn.

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