Monday, May 18, 2009

Polygonum cuspidatum: foliage

Warning: this is an invasive plant in Toronto. [Photo: Polygonum cuspidatum foliage.]Polygonum cuspidatum, known in English as "Japanese knotweed", "fleeceflower", "Himalayan fleece vine", "monkeyweed", "Hancock's curse", "elephant ears", "pea shooters", "donkey rhubarb", "Japanese bamboo", "American bamboo", and "Mexican bamboo", and in French as renouée du Japon or renouée du Siebold is a herbaceous perennial native to east Asia which is invasive in North America and Europe. SER Ontario ranks it as Category 2: "Exotic species that are highly invasive but tend to only dominate certain niches or do not spread rapidly from major concentrations." in their Invasive Exotic Species Ranking for Southern Ontario (PDF).

I photographed this plant at High Park.


  1. I've seen Japanese knotweed growing close to where my daughter lives .. huge stems, rapid growth. It looks lovely but I wouldn't want it in my garden.

  2. Oh so true. This plant has begun to get a toehold in Tommy Thompson Park on the Leslie Street Spit, and there's a stretch of ravine on O'Connor Drive just east of the bridge that is being homesteaded by polygonum.

    I narrowly escaped myself a few years ago, when I saw that my new (at the time) neighbour had planted it against our shared fence. I ran over to beg him not to ("knot" to?), and thankfully he was grateful afterwards. Otherwise, it could have been the end of our friendly relationship *and* my garden.

    The light soil here is like an open invitation to colonization.


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