Have you enjoyed those large, showy blooms of rhododendrons this year?

Many of us do not think about a plant’s specific care until it is in its heyday or in full bloom.

All rhododendrons, regardless of age, can benefit from a type of pruning called deadheading.

Deadheading means removing the blooms once they are over.

Removing those spent flowers will prevent the formation of seeds, which can use up extra growing energy otherwise used to encourage new growth and next year’s blooms.

If you decide to deadhead, be careful not to remove the growth bud at the base of each bloom. Removal of this growth bud will result in that branch losing a year of new shoots and leaves.

There are instances where you might want to remove that growth bud. This is most often done on a young plant to encourage branching, making the young plant a bushier, more desired form.

Training a young rhododendron in the early years will result in less maintenance later.

An established, mature rhododendron can benefit from thinning cuts annually.

Removing the oldest and weakest branches at the ground level will help to open the center of the plant, encourage new shoots and improve the shape. This pruning should be done in the summer after bloom.

If you have an old and overgrown rhododendron, rejuvenating it might appeal to you.

Rejuvenating a rhododendron can be done by cutting back one-third of the branches to a height of eight to 12 inches the first year, the second third of branches the second year, and the last third the third year.

New shoots should be encouraged by this type of pruning.

This new growth can more easily be trained into a desired shape.

Be advised that rejuvenating is a drastic approach.

It is a good idea to fertilize at least one year in advance if you plan to do this type of pruning. There are some types of rhododendrons that will not respond well to this type of treatment.

While pruning rhododendrons can greatly benefit a plant, it is also good to remember that some rhododendrons will live for many, many years and always produce a magnificent display of blooms even though they have never been touched.

Pruning is not the only wise practice for maintaining a healthy plant.

Care recommendations

Soil: Rhododendrons thrive in acidic soil with a pH between 4.5 and 6.0. They need well-drained soil to prevent root rot.

Sunlight: While some varieties can tolerate full sun in cooler climates, most rhododendrons prefer partial shade, especially from afternoon sun.

Watering: Keep the soil consistently moist, but not soggy. Water thoroughly but avoid letting the soil become waterlogged.

Mulching: Mulch with organic matter like compost, bark or straw to help retain moisture, suppress weeds, and regulate soil temperature.

Winter Protection: Protect rhododendrons from strong winter winds and freezing temperatures by wrapping them in burlap or using other methods.

Fertilizing: Rhododendrons benefit from acidic fertilizers, following the recommendations on the fertilizer package.

Pests and Diseases: Monitor for pests and diseases and address any issues promptly.

“Growing Green” is contributed by Diane Dorn, Lehigh County Extension Office Staff, and Master Gardeners. Information: Lehigh County Extension Office, 610-391-9840; Northampton County Extension Office, 610-813-6613