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Fallopia japonica
Japanese knotweed is a shrub-like, semi-woody perennial. It is fast growing and has hollow, bamboo-like stems that form dense leafy thickets 6-9 feet tall. Stems become tough and woody with age. The shoots arise from coarse, spreading rhizomes that can attain lengths up to 50 feet. Leaves are alternate, simple, and broadly ovate with pointed tips. The stalked blade is about 6 inches long by 4 inches wide. Plants produce either male or female flowers in white clusters at the upper leaf axils in late August and September. Female flowers can produce small 3-angled black-brown fruit, but seed production is rare. Giant knotweed looks similar, but is larger and has heart shaped leaves. Rhizomes allow Japanese knotweed to spread quickly and aggressively, although seed is sometimes produced. In North America, Japanese knotweed plants produce only female flowers therefore can not produce seed without a pollen source.
Japanese knotweed can be found in sunny areas along roadsides and in riparian areas such as river banks. Knotweeds thrive in a wide range of soil types. Some homeowners have Japanese knotweed in their landscapes.
Spotted on Nov 22, 2012
Submitted on Nov 22, 2012
16 Comments
Amazing color! Cool!
I agree with Anna. My hunch is that this is not Japanese knotweed - I've never seen one with autumnal foliage like this. The leaves of knotweed are not serrated and this plant stem seems far too woody - looks more like a tree sapling to me.
Lovely photo though - the colours are brilliant! :)
sorry but I'm still skeptical about the Japanese knotweed ID. Do you have any new leaves to look at this spring? http://www.phlorum.com/identify-japanese...
We had a slight frost early followed by warmth so that made the rainbow leaves, usually they are dark purple
Wow !
The foliage is purple because it was Fall and the leaves were dying which makes them change color. Normally they were green.
Are there Japanese knotweed cultivars with purple foliage? Please add some photos of flowers this spring. That may give you a definitive answer.
thanks for your help
Japanese knotweed is a good guess.
Could It be japanese knotweed the growth of the leaves and placement seem to match very well
I checked ornamental plum but it didnt look exact
It's probably an ornamental purple plum.
Leaves were originally purple, this is its fall coloration.
leaf shape looks like an apple tree, although I have never seen one with that color pattern. It may be something in the same family, Rosaceae
It's in my backyard growing among other weeds in a garden. Regular soil nothing special.
How unusual. What type of habitat did you find it in?