By Madmax
United States 
Need help with this plant what is it thank you
10 Jul, 2017
Answers
Maybe Epilobium parviflorum?
10 Jul, 2017
Whatever the species don't let it seed whatever you do or you'll never be rid.
10 Jul, 2017
The seeds fly around like a dandelion's, and the plants spread by underground rhizomes. It was quite a pest in Flagstaff, AZ, when I was going to college, there.
10 Jul, 2017
Previous question
It's a willowherb, Epilobium. Can't determine the species from this photo.
10 Jul, 2017