It could be. As in there is a resemblance

I did plant phlox in this spot - it definitely looks like yours - thank you! It has tripled in size and it was planted only last year. How old is yours @Sue Hughes Zone 6b in Pittsburgh?

Madreselva, Central NJ, 7a hi, somehow I got an email notification somehow for your comment, I guess because I quickly erased my "Phlox Blue Paradise" guess for this plant because I think your leaves have little saw tooth edges and I think mine are smooth, but I will attach the photo again since you saw my erased post, and let you decide. My neighbor has some tall phlox that are whit and they don't have the maroon shades in her leaves. Hope this helps.

Mine is two or three years old, and some just added this spring. It is a hardy, long blooming plant so I bought more, and it's starting to spread/mature. I was curious what kind of phlox did you plant? Do you recommend it?

I would guess one of the purple leaves Aster, if it’s not a Solidago.

Two more photos:

I can't wait until your mystery plant blooms!

Me too! do these look like yours?

Plus Phlox has opposite foliage.