Blind Shoots.

What causes roses to produce "blind shoots" , ie those canes that never produce a flower , does anybody know ?
I only have one HT here [Jacaranda] , that does it on a regular basis but several rose lovers on another forum I belong to, have been experiencing it as a real problem this year around Melbourne .
It has been suggested that perhaps it's the weather they have had this summer but I don't know if that is all there is too it or not.

It's not a major problem for me , I just prune the canes as I would any other and if the bush doesn't flower properly well I scarcely notice but for people that only have a handful of rose bushes if one doesn't perform it can leave a bare space in the garden.

So any suggestions anyone , as to what causes it to happen and what to do when it happens will be greatfully received and I can direct these people to RoseTalk to find some answers.

Thank You.
Rosalie

Rosalie a lot of D Austin's roses have this happening all the time, you can prune these blind shoots in half but it does'nt really seem to effect them flowering wise. I reckon it might be a trait from their breeding where climbers were used.