Do you know its name? The 7 leaflets would usually but not always, indicate that it is a wild rose possibly growing from the root stock. If the main rose has died, it's hardly worth keeping what is left.
Is that a yew next to it? I suspect that the rose has stopped doing so well as the yew has increased in size and competed for moisture and nutrition and shaded the rose bush.
I think that this autumn Id cut the rose hard back and move it to a better spot having prepared the soil and added some Fish, blood and bone and an organic mulch ... in the spring give it some rose fertiliser.
“I am not lost, for I know where I am. But however, where I am may be lost.” Winnie the Pooh
..well... you have to dig it out.. as much as you can.. it's not that difficult if you are fit enough and have a spade or garden fork.. from what I can see it appears your original rose is lost... sorry...
I'm not sure what you mean by 'tree'.. it's not a tree, but the rootstock has formed a shrub.. that's all you have left from what I can see... I would say your original rose is long gone...
Posts
I suspect that the rose has stopped doing so well
as the yew has increased in size and competed for moisture and nutrition and shaded the rose bush.
I think that this autumn Id cut the rose hard back and move it to a better spot having prepared the soil and added some Fish, blood and bone and an organic mulch ... in the spring give it some rose fertiliser.