"Black Fountain Grass" is probably Pennisetum alopecuroides 'Moudry,' common name Black-Seeded Fountain Grass. It's a great plant, and I have several, but it doesn't reach 3' in my zone 7 garden. It's only 3 years old, but it tops out at about 30" to the blooms. It can also self-seed prolifically if it likes it's environment, so unless you will be cutting the seedheads, or collecting the seed, you'll have volunteers.

There are hundreds of 3'+ ornamental grasses which would grow in your zone, but most of them won't provide a year-round screen for your utility box.

A dwarf Pampas Grass (Cortaderia selloana) variety would be semi-evergreen to evergreen for you, so you might look for those. The cultivars are 'Pumila' (5-7'), 'Andes Silver' (7') and 'Patagonia' (7').

Other tall ornamental grasses would have to be cut to the ground every spring, and would take several months to regain their height.

Thanks for the great reply.Now, I'm rethinking--hm-m--m-m-m
My original thought was a forsythia but then it loses its leaves in the winter. I know I can use something.
Catherine

Catherine..to stay in a grass vein, how about some evergreen hardy dwarf Bamboo? There's a new one called Fargesia rufa 'Green Panda' which is a lovely plant. It'll grow to 6-8' tall in time, and is a non-invasive clumper, hardy to -15°F.

Catherine, I just remembered another post on this same subject about a year ago - you might find some of the suggestions useful .....
A.

Here is a link that might be useful: How many zebra's should I use .....