Japanese Knotweed is springing up here along roadsides and waste areas of St. Johnsbury. It one of our listed species to watch for because of its incredibly aggressive nature of multiplying just from a small cutting. Since knotweed likes river banks and roadsides, hurricane Irene’s waters moved pieces of this plant to new areas where it has not been seen before. Since it can grow from a tiny cutting, all pieces moved by water will root and begin to both colonize and out complete native plants found there. As a community observer it is important to observe and report where this plant is seen growing.
One way towns are dealing with this highly invasive plant is to harvest and eat it at “if you can’t beat, eat it” festivals. People treat it like you would rhubarb in their cooking. If you plan to harvest knotweed, do so when the shoots are tender April to mid-May and DO NOT COMPOST the remains. Harvest and leave the remains right where the plant is found or dry out the cuttings fully before sending to a landfill. Cutting knotweed back reduces the amount of underground growth or biomass (spreads by rhizomes or underground stems) and limits the spreading of the plant.
Here is a link to a PDF of recipes for both Garlic Mustard and Japanese Knotweed:PDF
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Japanese Knotweed is an invasive weed which has destructive properties. It grows at an alarming rate of up to 10cm per day in any type of soil. In Scotland and Britain today, Japanese knotweed has become the most invasive and destructive plant known within our gardens and countryside.
The BBC did a report on the plant which tells you how to identify it and what can be done about it – http://www.wiseknotweed.com/japanese-knotweed-information/what-is-japanese-knotweed/
It really is one of those things you pray will never pop up in your garden. Personally I think your best bet where possible is to leave everything where it is since if you move it it’s controlled waste and use herbicides, well that or call some professionals.