Thanks guys!! Carrieb, I thought it was some anemone, just not Sylvestris (leaves are different, flowers smaller, etc). Lycopus, it was one of the fitting descriptions in the encyclopedia, what confused me was the description of the leaves & flowers: 5- to 7-palmate leaves, clusters of 1-3 flowers. Maybe I don't understant right, I thought they are 3-palmate, and looks like it's always only one flower. But what fits in the description is that it's spreading and invasive :)

There are many species of Epilobium, some of which have had name changes, like the fireweed. Some are native, some are introduced weeds. There's only one fireweed though, by whatever name. Watson's willowherb is a common garden weed, I think it's Epilobium ciliatum now, used to be Epilobium watsonii. Dry or damp, sun or shade, tall and rank or short and sparse. Seeds, no runners. The one in your garden is probably the Watson's although you may also have others like Epilobium minutum in dry spots. I'm sure bboy is much more knowledgeable about the various species than I am, I usually do well enough just going by 'Epilobium species'. What you have in the photos on the Weeds forum sure look like Watson's willowherb gone to seed. They've done really well this year with the cool damp spring. But the photos do need to be larger to really see. I'm just guessing from the silhouette.

thanks, will see, my David phlox is not close to the size of these plants. Which seems odd

Rough Buttonweed looks like it, floral_uk; and it does appear to be prevalent in our area. Coincidentally, in April I posted regarding a weed found in our St. Augustine lawn, and it was IDed as the dreaded Virginia buttonweed. I've had quite the struggle, constantly pulling (as no herbicides work, apparently) in the hot weather we've had. After 48 hours of rain, I'm in denial and don't dare look in that area as I'm sure the VB has gone nuts. After 26 years of home ownership and not experiencing any sort of buttonweed, I know have two varieties that the winds have blown in! Thanks, everyone.