How tall will my fruit bushes grow?

Three years ago I planted blackcurrant, white currant and gooseberry, which I bought from a reputable grower.  They are only knee high.  I remember picking a disabled neighbour's currants for her when I was a child, maybe four feet tall, and the bushes were taller than me.  Can I expect mine to get much bigger?  Might it be that I don't feed and/or water them enough?  I've never had more than a handful of fruit off them.