welcome to goy.

I assume yoy mean at the base of the rose where it goes into the soil. Just scrape it away using a hand trowel. Moss luckily doesn't have roots so it is lying on the surface.

I did a similar thing is a shady part of the garden at the weekend. I left the moss in a pile by the bird feeders and many birds took it away, I assume to line nests with.

If it is on the exposed roots near the base, I would put on a pair of "marigolds" and use my hands to pull it off. A trowel might take off too much bark, there.

Sorry to hijack Sheahan. Just wanted to thank SBG for that brilliant idea of leaving moss out for the birds. I've seen tits picking at moss but that didn't occur to me.