My neighbor is a landscaper and he often pulls plants from clients yard and when they tell him to take them he brings them home. Many of times he offers them to me so they get a new forever home if he doesn't keep them for his own! Today he offered me a Apricot Drift Rose that he he doesn't have anywhere in his fully shaded yard and I have a large backyard that gets full sun all day. My question is how can I combat the transplant shock that I know is inevitable by transplanting this late into spring???

The main concern will be to keep it watered. Don't drown it, but keep it moist.

Normally I would recommend pruning off the top third, so that the shocked roots have fewer leaves to keep hydrated. But drift roses aren't very tall to begin with, so use your judgment.

You could shade it with cardboard during the hottest part of the day for a week or two. That might help with the transplant shock.