I live far away from you, in a different climate, but I have experienced much the same as you. I have a rosebed made up of mostly peatmoss bought in bags, and the roses have been suffering from all kinds of anemia and deficiency symptoms. However two years ago I discovered that watering regulrly with a liquid type of fertilizer with all micronutrients made the plants healthy looking and growing well. Last year this was all I gave them. The type I used was very much the same as the non-organic version of Miracle-Gro. A few times I also watered in a weak solution of salpeter [Ca(NO3)2], alcaline nitrogen. This made the old plants grow and flower like never before, and I thought I had found a great solution for this bed. No other type of compost, or solid organic or non-organic fertilizer did much for this bed. This year however all the roses given this treatment are hardly alive, a couple of them completely dead. Non of the other roses were I only use solid organic fertilizer suffered any winterdamage to speak of, and I'm pretty shore this treatment made them very suseptable to frost damage. I though that giving a low nitrogen fertilizer from mid July through August would be enough to harden them off for the winter, but appearantly not.

These roses as mentioned are this year either dead, and all very slow to start growing, and they hardly have any leaves or buds compared to healthy roses. Symptoms of iron or nitorgen deficiency and very small leaves. I swear, growing roses organically in real soil makes them more winter hardy.

Even though you didn't use water soluble fertilzers like I did, your rose might have suffered similar winter damage to cane and roots. Major mistake on my part, but I suppose this can happen after an extra hard winter too.

You might want to try to cut her back to the ground and then see. At least that's what we were doing with winter damaged branches of bushes/trees in z5, since sometimes the branch can sort of leaf out, but the growth is weak and it is waste of energy to keep it going, since it will die anyways.

With roses that also may happen if they got waterloged in the winter, since that was usually the killer for me, not the frost itself. Or alternatively with the very strong dry winds, it can be sun burn damage, with some roses you have to protect not from the frost, but from spring sun and wind.

For this to come on abruptly this year after the rose was living happily and prospering, I'm sure it is not your soil or any deficiencies. And likely no amount of fertilizer is going to help. It sounds like the rose received a good amount of damage to its canes and maybe its root system this past winter. Despite the storm, we had a very mild winter but not without freezing temps; it could be a case of the rose was breaking dormancy early on then damaged by a deep freeze. Which could also explain the damage to your evergreens-not quite dormant, then burned by either freeze or sunscald.

Sometimes the damaged canes look viable in spring, but as the rose leafs out it becomes obvious the leaves are not being supplied enough nutrition and turn yellow and/or brown and fall off. I would do like elemire says and cut it back, and water well this summer. Maybe it will come back, or maybe not. Or maybe it will remaine alive but struggle along, and it will be up to you if you want to continue to nurse it along or replace it.

Could be salt damage. Try leaching the soil. There are lots of reports of salt damage from strong coastal winds. Most roses hate salt.

I considered that, but we've had lots of rain since then (plenty more than average), and that bed gets watered by lawn sprinklers for 30 mins. each morning (something I have no control over).

I have had a rose which suffered horribly from wind-rock (Queen Elizabeth wouldn't ya know - long gone now) which did exactly as yours - it simply did nothing. Have a gentle tug, you may feel if there was any loosening. You could do as Elemire suggested and cut it back hard - it will take any stress off the roots and it may act like a hardwood cutting, gradually rejuvenating a bigger rootball. I think you have little to lose by giving it a good stooling back. Good Luck