The Pacific Northwest has one of the finest rhododendron growing climates in the country. They are an integral part of many landscapes, and their variety is astounding. As the bloom season winds down in early June, it signals a perfect time to groom and prune your rhododendrons to keep them from outgrowing their space.
There are two types of rhododendrons. Elepidotes are large leaved rhododendrons. These are the types of plants that most individuals would associate as being a rhododendron. Elepidotes hold their leaves in whorls. Plants can become quite large over time. Lepidote rhododendrons have smaller leaves and are usually lower growing. Their leaves and branching rise from buds all along their branches. This group includes evergreen azaleas.
This time of year, as your rhododendrons finish blooming, you can keep them looking their best by doing some grooming. On elepidote rhododendrons, the flowers are often born in clusters, known as trusses. Breaking off the spent bloom trusses sends energy from seed production into growth. This process is known as deadheading. Lepidote rhododendrons usually drop their spent flowers naturally, or during dry weather, they can be brushed off the plant.
This is also a good time to prune rhododendrons. Light pruning now will not adversely affect next year’s bloom set. Elepidote rhododendrons can be pinched to promote compactness. To do this, break off single growth shoots. The the bud will push again, usually with multiple, shorter shoots rather than the single long shoot. Lepidote rhododendrons can be pruned anywhere along their branches.