If your cuttings are black, they are probably dead. There are many, many variables when it comes to plant propagation, so it would be impossible for one of us to tell you exactly why it happened to you in this case. It could have something to do with the type of rose you were trying to root, how well hydrated the mother plant was, the size cutting you were trying to root, and on and on and on.

If you'd like to try again, I have a photo tutorial on my web site (in the How To section) that has helped others learn to root roses. No hocus-pocus -- just no-nonsense instructions that should work for you. Give it a try.

Here is a link that might be useful: Hartwood web site

Growing cuttings can be iffy but after years of iffy I got a pretty good percentage this year. It's a little warm now in Ca. January was perfect and all the cuttings took. Two I was playing with now turned black so I tossed them. I mix Supersoil and cactus, succulant mix with a bit of vermiculite,drilled extra holes in the bottom of a 1 gallon black plastic pot a coffee filter on the bottom, layered with charcoal and than the dirt mix. These cuttings do well in patio sun and not overwatered and no fertilizer for a couple of months till there is substantial growth. Some plants just won't grow no matter what..