The Rhododendron genus of plants includes more than 800 species. The most common garden rhododendron is a flowering shrub that blooms in the spring in an array of colors, depending upon variety. Popular for their low maintenance and showy blooms, rhododendron are commonly used in hedges and as specimen plantings. Rhododendron do not require heavy pruning unless they are old or overgrown, in which case a drastic pruning will rejuvenate the plant. Prune the rhododendron when it has finished flowering.
Cut off all dead flowers, using the pruning shears. If there are buds, cut the stem to within 1/2 inch of them.
Remove all dead branches and stems.
Cut diseased wood back to a main branch. Do not drop the diseased branches onto the soil.
Severely prune an old or overgrown rhododendron to rejuvenate the plant. Locate the rhododendron’s primary branches. These are the ones growing out of the crown, at the soil level. Cut the primary branches back as far as 6 inches from the ground, 1/2 inch above a bud--the pink, pin-sized growths on the branches.