What to do? Advice please! Got an own root, bare root Quicksilver, along with several other Star Roses in the batch. Soaked them about 30 hours. All had large roots, but the QS was 2.5' long! Several others were also long, but QS was the longest. Realizing I didn't have pots deep enough for them, I heeled them in my large cart/barrow, in soil, no fertalizer, laying the roots horizontally ish. Kept the wheel barrow out of direct sun. I had to use big box store 'garden soil' with some organic potting mix, a little peat: all I had to hand. I did NOT dust the roots with mycorrhiza either. 2 weeks they spent in that situation while I made pots for them. Watered, checking for overwatering - kept moist but not wet. Nice shoots, leaves, everyone is happy. Four days ago, I wheeled the whole thing out to sit in sun, with partial afternoon shade. Pots almost ready. Yesterday, I noticed that QS looks like it's drying up. Leaves curling, wilting. Tested soil, slightly damp. Watered again (there are holes in the bottom of this cart, so no standing water is possible.) This morning, still wilted. I pulled the cart back to shade... pulled QS and put in light dappled sun, in a bucket of water. Checked for root bugs, or anything. One of the canes was black/dried. Pruned it off. Not sure what next to try....

tldr: QS dying. No standing water, moist. Too much sun? Should I fertilize? Water is city water, so alkaline - should I acidify? Should I prune back? Should I prune the roots? Those roots are so big, they do not fit in a 24" pot. I bought a 67 gallon pot yesterday, almost big enough? Should I put it directly into the ground?