[hogwarden]

I have 5 overwintering canes-Polka variety raspberry canes, 4 are shooting well at the base but one  has the start of leaf formation only at the top of the cane and nothing at the base. Do I leave it alone or prune it off to get some lower activity??

[sunshineband]

I'd leave well alone and let it grow in its own good time.

Some of mine are still not showing yet 

[Jamie Butterworth]

Mine have only just started to show

[viettaclark]

Polka are Autumn fruiting on canes that sprout from the base in Spring. Any canes that have over-wintered from last year (which should have been cut to the ground after fruiting last year to make strong new growth) will flower and fruit in the Summer. However the yield will not be so good.
I'm doing an experiment with some of my Polka to see if I can get 2 crops this year.
Won't hurt to leave them to shoot on the old canes now....see what happens......