Rhododendron PJM Varieties
PJM stands for Peter J. Mezitt, who, along with his father, developed the rhododendron hybrids that carry those initials. Since 1945, PJM rhododendrons have been used for mass plantings in the garden, as foundation plants and as specimens. Some PJM varieties grow up to 6 feet tall, while others have a lower, more spreading habit. The plant does not set seed. Flowers are bright pink, purple or lavender-pink and often arrive early in the spring.
Hardy in Zones 4 to 7, PJM Elite is an acid-loving plant that grows best in well-drained soils and partial to full shade, making the plant a good choice near trees and the shady side of the home. While the plant likes organically rich, moisture-retentive soil, it does not like its roots to stay wet all the time. Add acidity to the soil as needed and plant in raised beds if drainage is a problem. Elite grows 3 to 6 feet tall, 4 to 6 feet wide and produces showy, lavender-pink flowers in late spring. Like its PJM relatives, Elite is evergreen.
Regal also has lavender-pink flowers, but the blooms are not as bright as those on Elite. The plant blooms earlier and is not as tall as Elite, but spreads more bountifully. A vigorous plant, Regal does well in gardens from the U.S. to Canada, blooming as early as March even in colder climates.
Reaching a height of only about 4 feet, PJM Compacta is a semi-dwarf that makes an excellent foundation plant. The light pink or lavender-pink flowers appear in mid-March in most gardens. The plant blooms so vigorously that the small, rounded leaves may appear to vanish beneath the flowers. While winter tolerant, Compacta should be protected from harsh winter wind and too much sun. The plant is hardy to Zone 4.
PJM Northern Starburst
Developed by Briggs Nursery in Washington State from the PJM Compacta rhododendron, Northern Starburst has larger flowers, stems and foliage than its parent. Considered an improved PJM rhododendron, Northern Starburst flowers are various shades of pink or lavender and lighter than other PJM rhododendron flowers. The plant has a mounding habit. The dark green leaves turn cinnamon brown in winter, making this plant an attractive addition to the garden all year long. Northern Starburst is hardy to Zone 4 and blooms in late spring, depending on climate.