It is one of the most popular plants and can be found in almost every garden. No wonder, the rhododendrons are beautiful and totally easy to care for.
The rhododendrons form a genus in the heather family (Ericaceae) and are mainly native to Asia and partly to North America. They are among the most popular ornamental and garden plants in Europe and usually grow as bushes, less often as small trees and in exceptional cases also as large trees. The genus includes more than 1000 species, encompassing countless natural and cultivated cultivars. Very many of these varieties are hybrids.
Flowers, leaves and growth
Rhododendrons form trumpet-, bell- or bowl-shaped single flowers which open in sprawling flower clusters in spring to summer. Depending on the type and variety, the flowers can be white, pink, violet or yellow. The leaves, on the other hand, are elliptical to oblong and grow radially around the branches of the rhododendron. They are strong and dark green in colour. The foliage of most rhododendrons is also evergreen, but a few species shed their leaves in the fall.
The smallest rhododendrons are only about ten centimeters high. The largest species, on the other hand, can reach a height of more than 20 meters! However, these extremes are not typical of gardens and parks in Germany, but rather the medium-sized, compact and often spherical rhododendrons.
Popular rhododendron species at a glance
❒ Large-flowered hybrid:
The large-flowered hybrids form the most numerous group within the rhododendrons. They grow as compact bushes, are between two and five meters high and have leaves up to 20 centimeters long. The impressive clusters of flowers consist of up to 20 individual flowers, which, depending on the species, unfold their full splendor between March and July.
Large-flowered hybrids are excellent as solitary or group trees and sometimes as hedges. Well-known examples are 'Cunningham's White', 'Catawbiense Grandiflorum' and 'Furnivall's Daughter'.
❒ Small-flowered hybrid:
These hybrids have (often but not always) smaller flowers than the larger-flowered hybrids. The dwarf forms with a maximum of one meter are very populargrowth height, which are also very suitable for planting in tubs. These dwarf varieties include the small-flowered hybrids 'Curlew', 'Moerheimii' and 'Gristede'.
❒ Deciduous Azaleas:
The deciduous azaleas form a small group within the mostly evergreen rhododendrons. The varieties were mostly bred from British species. Well-known examples are 'Berryrose', 'Gibr altar', 'Lady Rosenberg' and 'Royal Command'.
Location and Ground
Rhododendrons love half or alternately shaded locations. Visually and ecologically, the shallow-rooted plants harmonize very well with deep-rooted trees such as mountain ash or oaks, which also provide the necessary shade. However, the foliage must not take away all the light from the rhododendron in summer.
The soil at the location should be water and air permeable, loose and fairly acidic. A pH between 4 and 5 is ideal. In addition, a high humus content is beneficial for he althy growth. You can find out how to properly plant a rhododendron here.
Important:
If the drought lasts for a long time, you must ensure that you keep the soil evenly moist. This goal can be achieved far better by frequent and slow watering than by the infrequent and hasty supply of large amounts of water. You can find more care tips for rhododendrons here.