Yes, exotics can take over the natural flora of an area if they're able with many down-the-road, harmful repercussions.
The two at top are Hydrangeas. While we can't grow them where I live, my South Jersey in-laws grow them very successfully!
Well how fun! You have some very nice pictures, TommyDaDelaware! Nice job! Love how you use the Latin name for correct and absolute identification. :)
Some of these I took, the rest my husband. We are very much into the native plants in our area. We even have our very own website...