Pruning a rhododendron helps control the size and shape of the plant. It also promotes healthy growth by removing dead or diseased leaves and branches.

Pruning is the judicious cutting or removing of parts of a plant to eliminate either diseased or unwanted parts. It enhances the shape of the plant, as well as its flowering potential. It is a common procedure to remove broken and diseased branches; enhance the shape of the plant by cutting unwanted branches or limbs, and increase light penetration and air circulation by thinning the branches. However, there are quite a few differences relating to pruning a tree, shrub, or a hedge. Pruning roses is very different from pruning a rhododendron plant.

The Rhododendron Plant
The rhododendron genus has over 1,000 species of flowering plants, which also includes azaleas. These plants have fibrous roots, and they grow well in acidic soil having pH levels of 4.5 to 5.5. However, some species also grow as epiphytes. These shrubs can be either evergreen or deciduous. Rhododendrons are widely distributed in the Northern Hemisphere and parts of Southern Hemisphere, including Southeast Asia and Northern Australasia. These plants are characterized by shrubs and small trees. They flower in delightful clusters of red, pink, white, yellow, and mauve.

The catawba rhododendron, or mountain rosebay, is an evergreen shrub that has dark-green leaves and red, white, or lavender flowers. P.J.M. rhododendrons, producing lavender-pink or white blooms, are the most adaptable and the easiest to grow. The flowers of this plant bloom in the month of April. The size, structure, and the glorious blooms make rhododendrons and azaleas top favorite ornamental plants for landscaping.

If you want to improve the appearance of your rhododendron plant, prune it in any shape you want by removing the dead or decaying branches. Pruning also promotes a denser growth of the foliage. However, certain precautions have to be followed while doing this.

When to Prune
The most favorable time to prune the plant is during spring, after its blooming period. It is advisable not to prune the rhododendron in late summer or fall, because it can make the plant susceptible to winter injury.

How to Prune
You will need sharp scissors or pruning shears, lopping shears, and gloves. Disinfect the pruning shears by rubbing alcohol on it. Knowing the species of your rhododendron plant will help you decide the type of pruning it requires. Rhododendrons are pruned mainly for three reasons.

Pruning for Shape Enhancement
Pruning a rhododendron accentuates its appearance. If done at the base of the plant, it encourages the growth of a dense foliage. Pruning also helps control the height and width of the plant. However, you should be careful while pruning a large rhododendron, because it might need a different technique. Shaping a broad-leaved plant is easier because it has longer internodes than the short-leaved ones. Snipping the stems an inch above a leaf or a node encourages a denser and more compact growth the following spring.

Pruning for Maintenance
Maintenance pruning is very easy and should be done every year in order to remove dead or diseased branches and spent flower clusters. Light pruning does not affect the flowering of the plant, if done in a careful manner. You can remove a diseased stem with a pruning shear, cutting just below the part that is affected. Snip off old flower clusters by cutting just above the new growths. You should remove the dead flowers from the plant in order to encourage new growth. However, do not snap the clusters with your fingers, as it may impact the new buds. Broad-leaved rhododendrons and azaleas benefit a lot from maintenance pruning.

Pruning for Rejuvenation
Rejuvenation pruning is best done in the winter months, when the plant is in a dormant stage. By pruning large number of branches, you can restore a plant which has become unattractive. This will lead to a vigorous growth the next season. However, it is better to prune above a cluster of three or four buds, because it promotes the growth of multiple branches. Rejuvenation pruning can be done by cutting three or four branches at alternating levels, it produces a distributed growth when the shoots mature. A heavier pruning is required if your rhododendron is diseased. Cut one of the main branches back to 6 or 8 inches. If you observe new growth from the cut, you can safely prune the remaining branches the following year.

Pruning helps maintain an attractive and compact shape. It also protects the plant from various diseases. In addition, you can mulch the rhododendron with a layer of pine needles and peat moss, which will ensure healthy growth.