Bamboo has a bad reputation in Maine, but it’s not bamboo’s fault.

Japanese knotweed, also called Japanese bamboo, looks like bamboo, but isn’t. It can grow ten feet tall or higher with stalks one to two inches in diameter. The stalks are segmented. Once established in a yard or field, it is a nightmare to get rid of. The Maine Department of Agriculture calls this plant “severely invasive.” The World Conservation Union calls it one of the world’s worst invasive species. Some people have nicknamed it Godzilla weed.

If Japanese knotweed looks like bamboo, how come it’s not bamboo? Because looks can be deceiving.

Here’s a quick review of how life is classified.

Plants are one of five kingdoms: the Monera Kingdom, Protist Kingdom, Fungi Kingdom, Plant Kingdom, and Animal Kingdom.

Each kingdom is subdivided into smaller and smaller groups of related members using these titles: Phylum, Class, Order, Family, Genus, and Species.


In the Plant Kingdom there is a Family of plants called Polygonaceae, which includes knotweeds, buckwheat, and other such weeds. They are weeds, not grasses. They are flowering and are dicots. That is, their seeds typically contain two embryonic leaves, or cotyledons.

There is another Family called Poaceae that is made up of grasses. These are monocots, their seeds typically containing only one embryonic leaf. There are around 1,500 species of bamboo in that Family.

I throw in this scientific mumbo-jumbo to point out that Japanese knotweed, though similar in appearance to bamboo, isn’t even a cousin.

Let me talk a moment about bamboo to make a point about Japanese knotweed.

Species of bamboo can be divided into two basic types: clumpers and runners. Clumping bamboo grows in a clump and stays put. It is the well-behaved sort of bamboo that gardeners and landscapers like. Running bamboo is not so well-behaved. It grows underground runners, called rhizomes, which send up new shoots elsewhere, sometimes a hundred or more feet away. This type of bamboo takes some effort to control.

Japanese knotweed, though not a bamboo, is a runner. To use a human metaphor, it’s both a sprinter and a marathoner. It grows fast and it goes far. And it’s tough. The root system can poke its way through concrete. It can damage foundations, buildings, roads, and retaining walls. It can take over yards and fields and river banks. And when it takes over, it won’t allow any other plants to share the soil, which causes erosion.

In the mid-1860s, a guy working in Japan sent a cutting to his brother in New York — probably thinking it would make a lovely ornamental. What he did was unleash a plague in this country that today is found in 42 of the 50 states, including Maine.

Though Japanese knotweed is hard to stop, there is a ray of hope. The shoots are edible, similar in flavor to rhubarb. The website, Eat the Invaders (, will tell you more.

Bamboo thanks you for your attention.

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