At first, I thought all the weedy smartweed mass in my vegetable garden was the Lady's-thumb Smartweed from Europe, which is very common in eastern North America. However, someone on the Facebook page of the Pennsylvania Native Plant Society posted some photos of this east Asian species and I recognized that what I had was this newer invasive annual of the Oriental Lady's-thumb Smartweed. The European species has a noticeable dark spot on many of its leaves. This Asian species also has a darker purplish spot on many of its leaves, though not quite as noticeable and a little farther up the leaf. This Asian species also has very long setae or bristly hairs coming out of its ocreas (node sheaths). Otherwise, it is not very different, and both are sort of pretty but powerful weeds. They are easy to pull out of the ground when smaller, but when they get big, it takes more effort to pull them out because of many stems with many roots holding onto the ground. So far, this invasive plant has been found from southeast Canada down to northern Florida to east Texas up to east Nebraska to southern Minnesota.

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