Donald, a few of things to consider:
1- Some species of Solidago have a more clumping nature (as opposed to some of the rhizomatous nightmares.)
2- J.C.'s plant appears to still be actively growing upwards.
3- J.C. only obtained the plant last year so it may be politely settling in while it quietly contemplates strategies to take over the entire garden.
Unfortunately, in my yard I have one of those wild, rhizomatous nightmare species that's bent on world domination.
EDIT:
Oops, posted before reading J.C.'s last post.
Regarding marking the thread "identified"...You can do either. If you mark it "identified," you can always change it later if you wish. People can still make new comments regardless.