17 responses to “Fallopia japonica”

  1. Tim Conant

    Thanks for today’s commentary. Knotweed is rampant here in the Boston area and threatens our parks designed by Frederick Law Olmstead. Dr. Jennifer Forman Orth’s website is very informative. Thanks for providing the link.
    Always grateful for your site no matter what you are featuring,
    Tim Conant

  2. Robin

    very invasive,and it is impossible to eradicate. The roots spread horizontally an spring up in the least expected places. One good thing, the shoots are edible in the spring, when they small, parboiled like asparagus!

  3. Mike

    I’m not comfortable with your term “invasive species”. Don’t plants have a right to grow where ever they can? Who decides what plant is invasive? Do you advocate the destruction of all apple trees in the USA? They are certainly not native and have replace habitats.

  4. phillip lacock

    mike, i am sorry, this is not about ‘friendly’ apple trees, that are planted on purpose, from root stock or grafts, these plants completely take over. i lived in placerville ca., scotch broom was introduced in a small area because of its rapid growth, erosion control, pretty yellow flowers,etc.
    today you can’t even ‘walk through the woods’, its only broom and pine trees, only rabbits and foxes can move through them, there are no more native plants where the broom grows, “invasive” means exactly what it says, dominate, aggressive.
    thousands of square miles of forest are now not passable to man,
    ‘O, look at all the pretty yellow flowers’

  5. Anthony

    Whatever, the broom, blackberries, and knotweed all three have a very attractive inflorescence. The most invasive species is still homo sapiens.

  6. Daniel Mosquin

    Apologies for taking so long to reply.

    I am entirely comfortable with the term “invasive species”. It describes the behaviour of these species quite well, as phillip has outlined: dominating, aggressive species that displace the natural fauna and flora. And yes, I favour eradication of these plant species when they are unwanted in non-native environments – I would much rather see one hundred different species of plants, insects and other organisms in a particular area than an impoverished landscape containing only a dozen common species (some of which are foreign).
    My conviction is that complexity (read: biodiversity) sustains and builds life. Higher numbers of different kinds of organisms result in more ecological and evolutionary processes occurring. In turn, the constant, changing complexity yields systems which can resist global disaster (e.g., moderating global atmospheric oxygen). For more on this, see The Roles of Biodiversity in Creating and Maintaining the Ecosphere (Table 3 presents a good outline) — disclosure: the paper is authored by my uncle.

    As for humans being the most invasive species, there is no denying the impact of humans on nearly every other species in the world. What separates us, of course, is the fact that we can think and choose. Fallopia japonica cannot do anything but grow and reproduce – it is biologically coded to do what it does, and when placed in ideal non-native conditions, it will do so very successfully. Homo sapiens can walk a different path, because choices can be made that would foster people living in such a way that integrates with and supports the rest of the living world, as opposed to diminishing it.

  7. Svitlana

    I am from Ukraine.
    I have flat in house near a dump. So I can observe big kinds of invasive species ( Ambrosia artemisiifolia, Cyclahena xantiifolia, Coniza canadensis and extras). Fallopia Japonica, too.

  8. Michael F

    I’m not sure this is Fallopia japonica – the leaves look a bit too elongated, and rugose with impressed veins. Maybe F. sachalinense.

  9. Daniel Mosquin

    I’d considered Fallopia sachalinense, but following the key in the Illustrated Flora of British Columbia, I came up with Fallopia japonica. The three elements from the couplet that suggested F. japonica were as follows: leaf blades squared-off at the base, 10-15cm long, the tips abruptly pointed. In comparison, F. sachelinense is described as having leaf blades heart-shaped at base, 15-35cm long, the tips gradually tapered. The other element of the couplet overlaps (1-3m tall vs. 2-4m tall).

  10. Tracy Austen

    I live in Ontario Canada and about 2 years ago purchased and planted a Fallopia japonica in my yard. It has not been invasive at all (the climate might be the reason for it not being invasive). I still only have the one plant that I planted initially. My mother has asked for a piece of the Fallopia and I was wondering if anyone knows the best way to get a new plant from the existing one. i.e. cut a piece off and root it or can it be divided by the root. Any information would be helpful.

  11. Daniel Mosquin

    Hi Tracy,
    The Global Invasive Species Database does list Fallopia japonica as being invasive in southern Ontario. As you haven’t given a more specific location, I don’t feel comfortable even directing you to possible resources.

  12. Jack Hamilton

    I live in an old country house in Eastern Ontario where I have a stand of knotweed that grows and shelters my south-facing porch each summer. Very nice – however, it has been working its way around the porch and into the basement where the odd strand shows up occasionally. The previous owner warned me. He excavated one side of the house and dumped the material at the back of the property. Guess what? I now have a new stand back there! As I clean out the dead stalks each fall, I dream of pelleting the residue and burning them in my pellet stove in the winter. Sweet revenge!

  13. Sabine Kloosterman

    To Jack Hamilton:
    Being a florist from the Netherlands, now living in Ontario I’ve been looking for knotweed for many years. I love to work with the stalks and create designs with it but have never been able to locate the plant in Ontario. Would you consider to share a piece of the plant with me?

  14. Tony

    I was curious if you are aware of a “compacta” variety that is less invasive to the point of being safe for the home gardener. My mother purchased the plan below. She didn’t know what it was so I took a picture and posted on a garden group and was directed to the possibility of Japanese Knotweed. I found this link that I believe to be the same thing. I am in Rockford IL USA (Zone 4-5).

  15. Joe Ward

    “Higher numbers of different kinds of organisms result in more ecological and evolutionary processes occurring.” Can you document this assertion? This sentence strikes me as being more of a conviction or faith-based belief, than a statement of documented fact. Perhaps it is mere redaction of a 20th century ecological “just-so” story. Fact is that lowland Amazonian rainforest dominated by one or a few species of palms exhibits some of the highest(nonagronomic) primary productivity in the world.
    “In turn, the constant, changing complexity yields systems which can resist global disaster (e.g., moderating global atmospheric oxygen).” Isn’t the introduction of a new species to an ecosystem an exaple of “constant, changing complexity”? By what criteria do you define “disaster”? Since when is the atmospheric concentration of O2 at risk of changing?
    “Fallopia japonica cannot do anything but grow and reproduce – it is biologically coded to do what it does..” And Homo isn’t? Witness exponential human population growth.

  16. Daniel Mosquin

    On the first point: “Diversity matters because both the chance of having certain species present and the range of traits present influence species interactions and abundances, which, in turn, influence population, community, and ecosystem processes.” from Tilman, D. 1999. The Ecological Consequences of Changes in Biodiversity: A Search for General Principles. Ecology 80(5) 1455-1474.

    Tilman also notes: “A myopic focus on diversity would be a poor management strategy, because diversity is only one of the many factors that influence ecosystem processes.”

    On the second point: the introduction of a new species, yes–that increases complexity. The dominance by that species to the point where it extirpates many others in the assemblage does not increase complexity.

    I clearly think a sudden atmospheric change in oxygen would be a disaster, so that defines the term. Is the atmospheric concentration of O2 at risk of changing? What does the past tell us? See: Huey, RB and PD Ward. 2005. Hypoxia, global warming, and terrestrial Late Permian Extinctions. Science 308:398-401.

    On the third point, I never stated that Homo isn’t. It is a pretty grim statement that even though we have a choice (e.g., intelligent decision-making) to moderate our biological imperative, we don’t.

  17. Frank Masters

    As an avid gardener and father to a tree nurseryman, I am hoping some one of your readers can lead me to some good means of control of meadow voles that are surely destroying our gardens and lawn.
    Traps are not a viable answer so far no poison bait has worked.
    We arw tempted to blow up the whole area but fear damage to house and neighbors windows.
    Has anyone tries CO2 fumigation?
    If so how was it expanded from liquid state?
    Thanks for reading this and any workable answers.
    FMM – Harrisburg, PA

Leave a Reply