That's Pennisetum alopecuroides 'Foxtrot' and it should start blooming any time now. It's a mid-summer bloomer, but may be a bit later in your zone. When mature, it'll reach 4-5' to the blooms, and about 3' in diameter. Cut it back to ~4" just as it starts sending up new growth in the spring.

Oops...sorry about the spelling. Got it from the tag that she gave me when I got it (would have been nice if they had any info on the back--but the plant co messed up and put the description for Alocasia 'upright elephant ears' on the back by accident!) Thanks for the info!

Just to add to Donn's thorough information.
In zone 5 Pennisetum's are quite slow to start growing in the spring. So ... don't get discouraged when it doesn't seem alive when most of your other plants are up and growing.
Many new grass gardeners have dug out plants of this particular species thinking it dead when it wasn't.