Q.Variegated ivy dying
i used fertilizer on my variegated ivy and all the new growth has turned black and died. Is there anything I can do to rescue my plants? The fertilizer I used was for feeding my privet hedge. I only used a very small amount on the ivy and it looked great for the first couple of weeks until the recent sharp frost, followed by strong winds and heavy icy rain showers. The plant is about 2 years old and I’m training it to cover a low southeast facing garden wall. I have 8 plants, each looking equally bad.

Sounds like your plants sustained a bad case of frost/cold injury, which is why the new growth turned black. After the danger of frost has passed, I would prune off the dead material, water it and wait for signs of recovery. Here is an article that explains further on how to save cold damaged plants.
https://www.gardeningknowhow.com/plant-problems/environmental/tips-for-saving-cold-damaged-plants.htm