Answer: Your hostas won't mind being divided now but your peonies might sulk and may even lose their flower buds due to transplant shock. If you can wait to divide them you won't sacrifice their blooms this year. If you can't wait until they're dormant to divide them, you should expect them to drop their current flower buds and perhaps not grow new ones at all this year. It's sad, but they are sensitive to being disturbed while they're trying to bloom. It won't permanently injure the plant to dig and divide now, but it may not bloom this year for you. I'd wait and divide them next fall, after frost has killed the tops back.
Hostas will be fine if dug and divided now in early spring.
Best wishes with your garden!
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