Answer: Azaleas and rhododendrons that grow that tall are hard to come by. I know of one azalea and one rhododendron that fit the bill. You are in USDA zone 5, the following are OK for that zone. The Piedmont Azalea (R. canascens) reaches 10-15 ft. in height, and has white to deep pink blooms. The rhododendron known as 'P.J.M' (R. carlinianum x dauricum) grows to approximately 6 ft., and has lavender-pink flowers. Remember, azalea and rhododendrons do not like frigid and harsh northern winds, they tend to dessicate the plants very easily.
Q&A Library Searching Tips