A bush started going near the back of our house. It has some thin, long pink flowers. Could this be a butterfly bush? The flowers just look way to thin to be a butterfly bush. Any ideas what else this could be?

Zee, are those unopened buds or small flowers? If they are buds could you post the flowers when open? That would really help.

I looked up the genus Buddleja to see if there are any close. Your plant has alternate leaves and there is a Buddleja alternifolia that looks something similar to yours IF those are unopened buds in your photos. I have personally never seen B. alternifolia so my confidence is very low with this suggestion.

Hi Kelly, thank you for your reply! I just went to see if they are buds or flowers. Looks like they are buds and some of them are just opening up into small white flowers. I uploaded another picture where you can see some of these white flowers. What I am wondering about whether this is just weed or if this is a shrub that I could potentially move to another part of my yard that needs more plants.

Flowers look exactly like Persicaria sp.

Quote wiki.....As of February 2019, Plants of the World Online accepted the following 131 species

Maybe...Persicaria lapathifolia...previously called Polygonum lapathifolia

https://en.wikipedia.org/wiki/...

persicaria
we call it ''smart weed''
will reseed ALL over and become a nuisance

Thank you so much for all your replies and identifying this plant! It is indeed Persicaria lapathifolia/smart weed! Thank you for letting me know that it will reseed and it will become a nuisance! I definitely won't transplant it and I will make sure I cut off the buds before they reseed!