Rhododendron hybrids

Ericaceae

Hybrid Rhodos

Size, shape and colour can vary a lot. They are however more commonly evergreen, medium or large shrubs. Some are smaller, and some are trees.

Generally, the leaves of hybrids are larger than those of rock rhododendrons and are not glossy like those of the vireyas. Rhododendron cultivars are usually referred to by their cultivar name only, and are known by the various styles that are easy to recognise. Alpine rhododendrons, for example, have small leaves, small flowers, a twiggy dense habit, and are very free-flowering. Rhododendrons from areas that have high rainfall are often fragrant and also tend to have large leaves.  

Uses

Garden shrubs, container plants, informal hedging or screening plants.

Culture

Cultural requirements can be variable; though most prefer full or part sun and a moist, freely draining organic soil.

Alpine species and hardy hybrids will thrive in exposure to full sun and wind. They are also extremely resilient to atmospheric pollution. These plants do well following an annual mulching in autumn to a depth of 8cm, which serves to protect and nourish the root system. This is preferable to breaking up the topsoil with a fork. 

Propagation

Cuttings

Cultivars

The earliest rhododendron hybrids date back to around 1825 with the introduction of R. arboreum. Since then a large number of hybrids have been produced using different species in different regions. Hybrids have been derived from: R. catawbiense and R. maximum (United States), R. arboreum (Himalayas), R. caucasicum (Caucasus), R. ponticum (Turkey), and to a smaller degree R. fortunei (China), and R. griffithianum (Himalayas). The majority of the hybrids derived from these plants are hardy, have dense foliage, and produce strong trusses laden with flowers. As such, they are referred to as the ‘Hardy Hybrids’. 

Plant Health

Healthy pllants growing in the right situation don't have a lot of problems; but many diseases are possible, particularly if you mismatch what you are growing with it's microclimate. Root rots in poorly drained soil, rust, occasionally leaf or flower galls, leaf spots, bud blast, powdery mildew, dieback, blight, bacterial diseases. Extreme cold can cause bark to split; and in snow and heavy frost prone areas, trunks might be wrapped with cloth for protection over winter.

Insects are occasionally an issue including thrip, scale, mealy bug, aphids and weevils.

More info

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