These pictures are of a "mystery plant" I received from a neighbor. I knew something was up when it grew almost 4 feet in two weeks. A little digging on the web turned up some useful information. It turns out that it is an exotic invasive. Japanese knotweed was brought to the US decades ago to control erosion (like kudzu). It runs rampant along wet roadsides and streams, especially in Appalachia. So, I will be ripping it up and replacing with either a red bud tree or camellia sasanqua this fall. As for my neighbor, I have forgiven him because he has given me a bunch great things (criniums, miscanthus, yellow flag iris). Plant swaps are a wonderful way to get to know your neighbor and your yard....as long as you know what you're getting!