The Rhododendron is a genus from the Ericaceae family. It is a very wide spread genus but the main concentration is found in the western part of China and the Himalayas. Rhododendrons are native to woodlands in the mountains. They prefer acidic and loose humusy soil and not too much sun. The soil has to be well-drained.

The name Rhododendron comes from the Greek words rhodos meaning rose and dendron meaning tree.

Rhododendrons usually grow wider than they grow high. They do not grow very fast. In general the given height in the specifications is the height that the plant reaches after 10 years. That also goes for the specifications on this website. The plants will keep on growing higher and wider but slowly.

Rhododendrons can be pruned easily. There are three common reasons for pruning:

  1. Maintenance
    Remove dead, damaged or diseased parts of the shrub. Follow the branch back to healthy wood and make a cut there just above a bud.

Removal of spent flowers is only necessary if the shrub sets seed. Then the plant can use its energy on growth instead of seed production. If the flower stalks shrivel and disappear after a few weeks, then the shrub does not set seed. It is best to remove the old flowers trusses (flower clusters) with a pruning shear. They are easily removed by hand most of the time, but you might break off the new growth with it.

This pruning is best done immediately after the flowers have faded.

  1. Shaping
    You use this type of pruning to alter the shape of the plant. You can do this in order to encourage denser branching or to control the width and/or height. The evergreen Rhododendrons hold their leaves for about three years. Cut just above the last whorl of leaves you want to keep.

This pruning is best done in the winter when the plant is dormant and is it does not freeze. This will sacrifice some of the flowers in the next spring.

  1. Rejuvenation
    This type of pruning is used to restore shrubs that have become leggy or otherwise unattractive. Most Rhododendrons can be severely pruned and come back as good as new. You remove most of the branches and stimulate vigorous flushes of new growth from the old stems. Over the years you can shape the new branches.

You can often even cut the shrub to about 6 inches (15 centimeters) from the ground. If you are not sure your Rhododendron will survive this hard pruning, you can cut one of the main branches back to 6 inches (15 cm) and the others less far (about 2 feet (60 cm)). If new growth emerges from the shortest branch, you can cut back the rest of the shrub the following year.

This pruning is best done in the winter when the plant is dormant and is it does not freeze. The plant will not bloom the next spring.

The Rhododendron ‘Cosmopolitan’ has large leaves and grows wide. The flowers are bright pink at first with a red flare in the throat. As the flowers mature they turn to a paler pink.

 

 

Attracts bees: no

Characteristic: evergreen

Deer resistant: no

Exposure: part shade/shade

Flower color: pink

Flowering time: April – May

Foliage color: green

Fragrant flower: no

Hardiness: -13 ºF (-25 ºC)

Height: 8 ft. (2.5 m)

Soil: normal/ moist