Looks like dog fennel, Eupatorium capillifolium. It's a weedy native and not typically part of a seed package. My neighbor has a huge stand of it. Dog-fennel Thoroughwort (delawarewildflowers.org)

Maybe no flowers, but it is decorative.

Carol, THANKS!!!!!!!!!! Thats it exactly!!!

It has flowers, and I think they are attractive. I've never seen the plant up here in the north. It's weedy reputation is how we view Ageratina altissima up here.

Are you positive it's not a cosmos? Some can get really, really big.