About four years ago, they got reall sickly, along with an Ancient Bridal Veil Spirea next to them.

The Spirea was down to one main branch and the roses quit blooming.
They have both come back now but what would cause such old plants to look like they were on deaths door?
The Peonies and Lillies of the Valley around them were healthy.

If you are very partial to these roses I would start rooting some cuttings of them this year while they are healthy as an insurance that you won't lose them in the future.

The Spirea looked like a Spirea down to one main branch and the roses looked like (I do not know if you know what "June" or old fashioned rose bushes look like) but take healthy stand and remove almost all the old canes and leave a scattering, maybe twenty five percent of what was once there, of new young canes with no flowers.

It took two years, after the dying stopped and then they stared growing again in a normal way.

These roses were there back when we had two very large Box Elder trees and an Apple tree all within thirty feet forty years ago and they were even bigger then.
The Spirea is just as old.

Here is the odd thing, now that they are back to normal, they are becoming a pest by branching out into the Lilies of the Valley so I have to dig them out of there.

It just makes no sense to me.
I even accused my brother of poisoning them, he never liked them, which he says he did not.
As he loves that old Spirea did his best to nurse it while it was sick, that kind of negates that.

Can bad nematodes cause something like that?