Odd problem with Roses - no leaves - plenty of blooms

 Hi,

I've got an odd problem with several of my dark red roses - they have very
few leaves - but plenty of blooms. Sometimes there are no leaves on the
cane. It is a BlackBoy variant. Not much of a  scent. Not a climber.
Multiple petal diamond shaped rose flowers.

What can I do to encourage it to have more leaves?

Could it be due to the fact that they were cuttings which I placed into the
ground after about 1 year in a pot?

Or perhaps its just a case of black spot?