Most importantly - and I'd presume they are - are they hardy roses? Zone 4 or lower? Basically you have three options if they are:
1. Bury them in leaves or hay after the ground starts to seriously freeze
2. Bury them in leaves or hay after the ground starts to seriously freeze THEN cover them with row covers to keep the leaves in place.
3. Do nothing. If they are really hardy, and you planted early in spring they should be mostly fine especially if we get snow.

Best possible thing will be if we get a good deep early-ish snowfally, then you put the leaves OVER that - best insulator. Just covering them won't insulate the roots which is what you need to achieve- holding the temp just at freezing so they stay dormant but don't die. I have one zone 6 rose that I literally bury in compost, then deeply in leaves, then put chicken wire over to keep them in place. I have to cross my fingers every spring (it was from my dad, it's a special rose and very rare now) that I got it deep enough.

If they are NOT particularly hardy roses - your best option is #2.

-Marie