In my experience Nassella (Stipa) tenuissima is only hardy to zone 6. Some growers list it as only a 7.

Mexican Feather should have been a dead give away.
However I have seen in my area, what looks to
be MFG. I doubt if I stopped to ask where
they got it they would even know what kind of
grass it was.

Any dead ringer for MFG?

Since I have the seeds, I am going to go ahead
and plant them, other wise it would be a waste of
money. Still might be ;-)

Thanks Grass Guy

It can be grown in colder climates as an annual. However it seldom will develop sufficiently to bloom or set seed, so reseeding in your zone may be problematic.

Thank you Garden Gal.

I really love the whispy look of it as
it blows in the breeze.
I would love a smaller grass for my slopes
and my rock garden that I can just leave
be.

Mary
z 5b KS

A couple of other "whispy" grasses, hardy in your zone, are Festuca ovina and Nassella viridula.

By all means plant them. Maybe do containers. I saw a really nice container of Nassella at Longwood Gardens in PA. I don't know if it was a hardier variety or not, or what they may have done with the container in the winter, but like Gardengal said...use it as an annual grass.

Donn,
Thank you for the grass suggestion. I will look into
both of those.

Grass Guy,
I can see where that would be very cool in a large
container. I wonder what I could plant it with
to set it off? Food for thought!

Thanks everyone for all of your
advise on MFG.

Mary
z 5b KS