Natalie, you are very welcome!* If you can't find perlite where you are, see if you can find some type of rooting medium or well draining potting soil.* Even orchid potting medium should work if it's bark chips.* It would allow for drainage but still stay moist enough for the roots not to dry out.*
I forgot to answer your question about what the roses need.* I'm thinking you will be planting this rose outdoors, correct?
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant.