Boo Hoo! I accidentally broke off all of the foliage on my Kiri Te Kanawa when planting it. I did plant it deep and used a lot of compost and cow manure I also plan to dose it with SuperThrive when it arrives. I had to order it because I couldn't find it at HD, Lowes, Ace or the one independent nursery/garden center I checked. Will it survive?
I'd wait until spring. You really don't want excess new growth that would be hurt by winter. You can resume with the Epsom Salt drink in late February/early March when you examine the plants and see "new bud break".
See the new buds expanding in this photo? That's what you're looking for as new bud break. Then you can cut it back to 12 - 18" from the earth and begin feeding. Too much food is not helpful to plants or humans. Follow directions on labels for best results. It may sound dated to say that but it's true.