Posted: 28/04/2012 at 13:16
Are you sure that you haven't had a sucker come up on at least one of the roses? Check if the branches come from above or below the graft (a knobbly section just above the ground). If they come from below they are suckers coming from the rootstock, which is different from the normal flowers. It will probably have leaflets which are a paler green than the rest, too.
If they are suckers they need to be removed by cutting off as close to where they emerge as possible. If you don't do this they will take over the rose and the graft will eventually die, leaving you with only the suckering shoots and their flowers.