The PJM rhododendron is an evergreen shrub, but instead of having green leaves all through the year, its leaves are mahogany bronze during the winter and flowering season. In the summer, the foliage turns green. This attractive shrub has small trusses of purple flowers. The PJM rhododendron shrub grows to a height of 4 feet and is 4 feet wide. PJM rhododendron is hardy to temperatures -20 to -30 degrees F. Pruning the PJM rhododendron is easy and needs to be done right after the flowers fade.
Prune the PJM rhododendron in the spring after it has finished blooming. Do not prune the plant in late summer or fall, because this can make the plant more susceptible to winter injury.
Disinfect your sharp scissors, pruning shears or lopping shears with rubbing alcohol. If your shears have a disease from another plant on them, the alcohol will kill it.
Remove old flower trusses. Simply cut the truss a half inch above the emerging new growth. Resist the desire to use your fingers and break the flowers off. You can remove too much of the new growth this way.
Remove any damaged branches or wood caused from the winter or storms.
Check over the PJM rhododendron for any diseased stems. You can spot them quite easily. Look for leaves that are wilted, curled or yellow in color. When you prune away the diseased part, make your cut below the diseased part and into the healthy wood.
Pinch out soft new shoots of the rhododendron. This will improve the form of the plant, and help it to fill in more solidly. Do not pinch back after July or you will ruin the blooming in the spring.