when are you going to plant the rhizomes especially you are in zone 4?

some of them usually go out about May 1 (My back yard is not normal for here---I've built myself a microclimate out back,,,,,,quite well protected) worked for me the last two years. Plus these are all raised beds and tend to heat up earlier.

what does microclimate mean? Someone told me this before in hydrangea forum. How did you build it?

The climate of a small, specific place within a larger area. An area as small as a yard or park can have several different microcliments depending on how much sunlight, shade, or exposure to the wind there is at a particular spot. My back yard happens to be sandwiched between two homes (24' apart,half mine) which close off the east and west sides, and I have a shed closing off the north/west side of the northern opening with a large maple tree closing off the balance of the north end. A very protected area from the prevailing winds and all the cold north winds.