Are you looking for a rhododendron that grows bigger than a house? This old variety from England does just that. It takes lots of years, but will make a huge plant that flowers heavily every year. The plant was created in the 1850's by Standish & Noble Nursery, and is still propagated and grown today. The cross between the species R. catawbience and R. griffithianum was quite a successful cross, and very large plants can be seen here in Eureka, California as well as in England and New Zealand.