I spent several hours yesterday working against the expansion of the Japanese bindweed (Polygonum cuspidatum) in our yard. Japanese bindweed, aka Japanese knotweed, is an invasive species that was introduced to the U.S. in the 19th century. It has since spread over most of the U.S., and has reached Alaska.

It grows by means of seeds and rhizomes. It grows rapidly into tall stands that block out the light to native plants. Once established, it is difficult to eradicate.

I was tired of looking at the tall dead canes of last year, and when I saw the abundance of new green shoots, I decided to take action. Here is a picture of the young shoots:

I cut down all of the green shoots and snapped off nearly all of the dried canes. Now I need to get the last of them torn off, then raked into piles. After that I plan to dig up the rhizomes. They are just under the surface–not deeply buried. Here is a picture of the dried canes (last year’s growth):

For all of you Harry Potter fans, it is possible that this is the species of knotweed used in the creation of Polyjuice potion (Chamber of Secrets, Goblet of Fire, Order of the Phoenix). There is another species called knotweed (Paspalum distichum), but the potion is called “Polyjuice.” Is the “Poly” derived from this Polygonum cuspidata, which is also invasive in Britain? I’ll have to post a query on J.K. Rowling’s site.