PJM' was introduced by the Weston Nursery in Hopkinton, Massachusetts and was named after its owner Peter J. Mezitt. Aglo' has light pink flowers with dark pink throats. Introduced by the Briggs Nursery in Olympia, Washington in 1998, ' Northern Starburst ' is the first release from the Genesis series of tetraploid rhododendrons. In the fall, the dark green, glossy leaves turn to cinnamon, eventually darkening to purple-black. Several varieties of Rhododendron catawbiense are other possibilities.
Catawba rhododendrons require a protected site and do best in southeast Iowa.
An exciting new group of large-leaf rhododendrons are the Marjatta hybrids . Developed at the University of Helsinki in Finland, the Marjatta hybrid rhododendrons have broad evergreen leaves and large showy flowers. Haaga ' has an upright growth habit and will grow up to 6 feet in height. Elviira ' is a low growing, spreading plant with a mature height of 2 feet. Its flowers are bright red.