And where are you ?

Hartsville, SC, z8 very sandy soils

Here's another pic:

Sort of reminds me of Milkweed plant.
It can get really tall, mine are and they are young. Especailly the tropical kind.
They don't need alot of water either.
If it is milkweed, I don't know why it's not blooming.
Does it get alot of sun/
Well, see if you like it this year, whatever it is.
If you don't, you can always just pull it out and plant something else.
Google tropical milkweed. See if it looks like what you have.

Looks like Maximilians Sunflower to me. The leaves are bit narrow but that could be because of the location. Wait til fall when they bloom. They're one of the prettiest wild flowers out there - but they will also take over the world and require a lot of work to keep in line.