Paul,
Sorry to hear about deer damage to your roses.
Short answer: Liquid Fence weekly or biweekly along with a tall peripheral fence. Roses inside the fence mulched with 8" river rock.
Long Answer: When I moved to Prescott, AZ I bought a property with a fenced area. I knew deer would jump over it; but I planted roses nonetheless. Third year I was here I went into the garden to inspect the roses. Twenty or so of them had wonderful buds on them. "Ahhh," I thought, "Tomorrow I'll have a lot of great roses." Got up the next day and looked at the garden. All the buds had been eaten by deer. They jumped right over the fence.
I bought those sprayer thingies that detect motion and spray water. They scare deer, but I forgot to turn one off one day when I was in the garden and got an unpleasant surprise. Furthermore, the things seem to start going bad after a season. Between forgetting to turn the water on and dead batteries, they often do not work when you need them most. In my garden I judge them to be a little more trouble than they are worth.
I started using Liquid Fence. Made of rotted eggs and cayenne pepper, I think it actually smells pretty terrible. If I use it religiously, every two weeks or so, I find that the deer and other nibbling animals tend to leave my roses alone. When I do spray, I concentrate on marking the periphery of the garden, then on spraying the established leaves on roses showing new growth. Sometimes new-growth leaves are stunted by the concoction, I think. My impression has been that very regular, light spraying is much more effective than rather irregular drenching.
The acid test of this has been to plant roses outside the fence. For some time every single rose I planted outside the fence was nibbled to nothing before the first six leaves had hardened off. Then I got serious about using Liquid Fence regularly. I'm finding that the damage is much less frequent. I will know a lot more in fourteen months, because I have planted a number of new roses in the area this spring. One of the things that has changed there since my early attempts is that I've planted a lot of deer and rabbit resistant plants - agastaches and so on (High Country Gardens) - enough that one can detect their odor on a still day. I think this helps amplify the 'no food here' signal from the Liquid Fence. Or maybe it helps bridge gaps in delivery.
One last thing about fences. When I gardened in NJ I put up a 6 ft tall cedar fence. For about two years deer would jump it to get inside. But I was growing roses around its periphery. One day I saw that a deer had crushed a nice, mature Autumn Sunset in jumping over the fence. I was sorry for the damage to the plant; but I know that the deer was a lot sorrier. That was the last time a deer came over the fence. Here in AZ, plants and boulders around much of the periphery stop deer from jumping over the fence; but there's a section with open grassland. Good news is that the soil here is very soft sand; so the deer have difficulty jumping in it, and making a 4 ft fence almost good enough to keep deer out. Then I put river rocks along the fence - 8" diameter rocks over the length that is ajacent to the grass, extending from the fence to 8 feet inside. And I planted roses here. The deer find it impossible to jump from atop these rocks. They get trapped inside the garden. This really spooks them. Since one got trapped there, I watch the deer walk by studiously avoiding it. I still spray liquid fence on the section of fence deer use when they jump into the garden.
It's still early in May, and the big rosebud nibbling surprise happened about a week later in the season a few years back; but since the deer got trapped in my garden in February of this year, I've seen no signs of deer damage in the fenced garden. Only the flower stalks of my yellow and pink iris outside the garden have been eaten. Sadly, Liquid Fence does not adhere to iris foliage.
I think that having a multipronged approach that changes from time to time is likely to be most effective in the long term; so it is useful to have a good bag of tricks.
Good Luck.
