That's the way I've done it. I am not sure how long to leave it before checking on it. I think I left mine through the winter.

And from what I've seen, success varies from rose class to rose class. For example, ramblers are derived from R.multiflora and/or R. wichuriana and get their ease of rooting at leaf nodes from those roses. Often the roots come quickly everywhere the leaf nodes are in contact with the ground.
Other roses are a lot less eager to layer (Charles Austin- I gave one cane three years of ground contact and nothing happened.)
OTOH Frederick Mistral cane rooted along a broken cane and the resulting bush is now indistinguishable in size from the original. Because FM is under patent, I didn't sever the connection, but after six years, I expect it no longer exists.

at least wait a year, or even longer