in my posting about Fallopia japonica (Houtt.) Ronse Decr. (Japanes knotweed) from July 19th, 2011, I didn't show you any pictures of the inflorescences, because the flowering time of this plant starts within August. Meanwhile I've found many individuals with flowers, so I've some pictures of the panicles, but don't ask me, if these are male or female flowers.
F. japonica - inflorescenes
If you remember, I also mentioned, that F. japonica is a very problematic plant, because it's an aggressive invasor, which can overgrown places very fast. I showed you a picture of a stock, but this was not very impressive. But now, I've a very imposing picture for you.
F. japonica - stock
Yo, this is all F. japonica. This stock grows next to a train station in Solingen, Western Germany. Now you can see, how fast this plant can spread; just compare the size of the stock with the platform of the station.