The early signs of fall can be seen in certain black gum and sassafras trees that already have leaves turning shades of red and crimson. The ironweed and cardinal flower are in bloom, adding splashes of color to meadows and streamsides. Goldenrod is just fading, its yellow blossoms still attracting pollinators.
There is one non-native plant that is also blooming, one that many landowners regard with disgust as this aggressive interloper spreads with abandon, particularly along streams and rivers – anywhere that is sunny and moist- including sections of parks, lawns and roadsides. As naturalists, we know the story all too well as it has unfortunately been repeated often in the landscape industry: an ornamental introduced due to some positive trait which escapes the confines of yards and gardens and grows into a menace for our native ecology.
Such is the case with Japanese knotweed (Fallopia japonica), first introduced from Japan in the late 1800s as an ornamental, valued for its profusion of small white flowers in the fall and its habit for colonizing quickly.
It resembles bamboo but is not related, instead belonging to the buckwheat family. It is currently found in 39 of the 50 United States and listed as an invasive in 16 of them, including Virginia. It has spread to Canada and is found in all provinces except Manitoba and Saskatchewan. The extensive land area in which Japanese knotweed can flourish is due to its amazing hardiness - it can survive in areas with winter temperatures as low as -31 degrees and flourishes in many types of soils with varying pH levels.
Its reputation as a noxious invasive is supported by its monster growth habit- with roots which can extend 10 feet down and spread up to 28 feet horizontally, it can get started by one small section of root being brought in with a delivery of mulch or hiding within the soil of a potted plant. It can be extremely difficult to eradicate once established.
In fact, it has become such a serious invader in the United Kingdom that property values are decreased and when trying to sell, landowners have to declare the presence of Japanese knotweed on their property and detail their ongoing eradication methods. Some properties may become unsalable due to the presence of the monster since it can crack cement walks and buckle asphalt, impacting building foundations.
We refer to one of our favorite foragers for guidance on the culinary uses of Japanese knotweed and sure enough, Euell Gibbons (1) recommends it as a versatile food. In the spring, the early shoots can be harvested when a foot or so high (before leaves begin to unroll), boiled for three to four minutes and enjoyed with a bit of butter and salt. If it is too tart, a small amount of sugar can be added.
He notes that the asparagus-like tips can be boiled or steamed, pureed with butter and salt (and a sprinkle of sugar) and served as a hot soup. Extending into the dessert realm, Japanese knotweed lends itself well to jams, sauces and pies. When cooked into a pie, the stems are a good substitute for rhubarb.
Now is the time to scout out the colonies of Japanese knotweed for spring foraging as they are at maximum height - six to ten feet tall - and are in full bloom. Good luck spying this noxious invasive and maybe helping to control it just a small amount by eating it!
Euell Gibbons, Stalking the Wild Asparagus, Field Guide Edition, David McKay Company, New York, 1962, p. 109.
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ORMN Class IX