Answer: I would leave the boxwoods alone for now. With any luck, only the leaves were affected and not the stems. Allow time for the boxwoods to recover. If they don't develop new leaves by the end of the summer, prune out the winter kill and wait for next spring's burst of growth. Let's hope they recover!
If your irises are not performing well, now would be a good time to dig and divide them. While you have them out of the ground you can amend the soil with organic matter (spread 4-5" of compost, aged-manure, shredded leaves, etc. over the top of the soil and dig it in to a depth of 8-10"). After amending the soil you can replant your irises, just 2-3" beneath the soil surface. Amending the soil and dividing the iris rhizomes will go a long way in improving their performance. Although they will tolerate some shade, they'll grow and flower best in full sunshine.
Best wishes with your garden!
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