I don't think it will show new growth till May if pruned now.
Or maybe it would :-)) I just checked my photos of a short grafted piece of greggii.
This was taken on March 20th '06:

{{gwi:493715}}




and this was taken on June 23rd '06:

{{gwi:493716}}




So, if the tuber is healthy and the weather warms up finally it should work!
Good luck.

Jordi

Thanks for the info Jordi. Now I need to make up my mind to chop or not.

If you chop, try to root the cutting. It usually works and then you have a gift-plant to make somebody happy.

Jordi

Definitely, won't let all that old growth go to waste.