Help-Is My Pampas Grass Dead?

Last year, I planted two plants of pampas Grass. The stuff took hold and grew well, although it did not form a plume. We had a long hard winter (I live in NE), and I cut back the dead grass in the spring. Now, I don’t seeany evidence of new groth-is the grass dead?
I’m told that pampas Grass is pretty tough-how long should I wait before ripping the rootstocksout and trying over?
Anybody have experience with PG? I’m toldit is considered a nuisance in California.

It is pretty tough stuff and with the hard winter we had, we are about a month behind in the growing season. All of my plants are just now starting to take off. I say give it a little more time. I did notice that Pampas is one of those edge of the zone types so it may not have survived the extreme temps we got last year. My gardening book says zones 7-10 which is 0-40 degrees Fahrenheit.

The grass is not dead… it cannot be killed by conventional methods. We used a weedeater with a solid blade to trip ours back, and then a chainsaw to level it. We poured some gasoline on it and let it burn for an entire day. Rinse, repeat for 2 more days.

It came back. We had to dig up the root to get rid of it.