Potatoes with no flowers

I have grown Charlotte pots in old compost bags and layered them up and now the green tops are at least 18" out of the top but no flowers - are they just a bit late or have I done something wrong? :confused:

 

Not all pots flower, some just drop the buds.
Dont know about Charlotte, but its nothing to worry about.

 

mine have only JUST started flowering - only a couple of flowers. I'm sure they'll come eventually. I think you harvest all spuds once the growth has died back, so just wait till then, unless someone tells you different