Answer: It sounds like winter damage. Often, plants with tender buds will flower only on the lower branches, where they were insulated with snow cover. You may have better luck if you wrap the shrubs with burlap. They are quite sensitive to dessication from winter winds. Also, make sure they go into the winter with plenty of soil moisture--keep them well-watered through the fall so they have an underground supply once the ground freezes. I don't think it's a fertilizer problem, since you do have blooms on the bottom branches.
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