If they are small enough (1″ trunk diameter or less) and you can dig them up without damaging the root system much, then you could pot them up in very large pots and keep them over s the summer in them an replant them in fall. They should be dug and potting as soon as the ground thaws while they are still dormant. Once they leaf out, it is too late to dig them without killing them. If they are larger, digging them out will probably kill them.