This is coming up like crazy in my garden this year -- fast growing and lush! What is it?
Looks like Conyza canadensis.
Looks like goldenrod, Solidago sp.; there are many garden cultivars.
I agree with Tedhort, Conyza canadensis.
I think it's Solidago canadensis, the rambunctious one.
I believe if it is Solidago, you will find the plants connected at the roots, with long runners. I do not think this will be the case with horseweed.
That is true, carol, a good way to figure it out.
Although either way, I imagine this is considered a weed.
Thanks for all the replies!