Don't cut it until after you see which branches produce leaves - probably late April or early May. Once you determine which branches are really dead, then you can cut the dead out.

Well, it partially depends on what species of Passiflora it is, but for the most part Passiflora can be heavily trimmed, but not all the way to the ground. I agree with kayjones above that you should wait until you see new growth. I had an 11 year old P. caerulea that I had to cut back very hard due to it being strangled in a chain link fence, (yes, the branches are that big), and it actually did better the next year than it had in several previous. I think the most important thing is to make sure you do it at the right time of year, when new growth is beginning to break through. Don't wait till it gets too hot, and don't do it when there is still chance of freeze.

There's my $.02...

Eric

Thank you for your suggestions friends. How much back can I cut the live steam? Can I cut it to ground?