One of my favourite subjects~~~~~~~~~~~~~~
Basically you cant get rid of them but you can restrict them -find their hiding places- bits of wood, garden debris,under pots,dark places where they hide in the day-go out in the dark with a torch you will see them on the plants-pick them of and dispose- early this morning they were about.
If you anti. the blue pellets there are wild-life friendly ones available
You will never get slugs or snails out of your garden- but it is fun trying
There are lots of helpful people on this site -ask away -someone usually knows the answer.
What sort of roses? Climbers, ramblers, bush...?
After a recent dinner party as my guests; a mother and her 14 year old son were leaving at 10.00 p.m., we noticed about 50 snails around the front door so we spent a pleasant 20 minutes 'snail hurling' into the field behind. I can recommend this as good vigorous excercise.
You really do need to go out at night with a torch and have a look, you'll be staggered by the number of them around especially during warm wet periods. I tend to deal with them by using something sharp and planting a patch of some cheap plants, that I know they like, to tempt them to a certain area (50p trays of unloved Marigolds from B&Q were this years choice). Snails get a slightly more under foot treatment.
You can also use beer traps and there's a thread on here about a flour trap somewhere. All the methods mentioned work, you just need to pick one and stick with it when there are plenty of them about.
We have used broken eggs shells with great success,dry them first,break them in to smallish peices,and place around affected plants,more shell the better,if you know someone who works in a cafe or restaurant, ask them to save the shells for you...good luck....