Helen Curtis is 3x3; Pleasant White is 4x4; so is R. viscosum and Girard Kathy. Search the internet for Girard Hybrids, Northern Lights Hybrids and Exbury Hybrids. These should be cold hardy. Verify that they are good on Zone 5 & have the appropriate height that you want (4') and then try to view a picture as some white azaleas actually have slight pink undertones or colored blotches in the center. Inquire too with local nurseries. Luis

Luis, thanks for the suggestions. I'll check them out. Sophie