What is this weed?
It seems to like the shade and gets pretty tall 4-5 feet. It doesn't (does it?) have flowers.
Pretty sure you got a horseweed....they grow much taller and lankier in shade...I get them in sun and if left go they can reach 4 ft, but I usually yank before that. When I first moved to this place I had a ton. They are annuals and easy to pull up.
Here is a link that might be useful: Conyza canadensis
No its not horseweed. I've seen that and it looks different its less branchy than this one:
Here is a link that might be useful:
Looks like some kind of aster in the second picture.