The Genus Rhododendron
The interest in growing rhododendrons has increased greatly within the past few years and the demand for the newer and better types of plants and the desire for cultural information has been created. The newer and very superior hybrids and the magnificent species from the Himalayan Mountains are being grown as successfully in America as in Europe. The genus Rhododendron, belonging to the Ericaceae, or heath family, contains approximately 700 species. From this vast collection of native forms of rhododendron, many hundreds and perhaps thousands of hybrids have been created.
Hybrids and Species
The distinction between hybrids and species is simply that the species rhododendrons are those native forms from various places of the world which will reproduce themselves true to form from seed. Hybrids are new varieties which have been developed by taking the pollen from one blossom to fertilize the seed of another blossom, thus creating a new form. These crosses are made by cross-pollinating one species with another species, one hybrid with another hybrid, or by crossing a hybrid with a species. It is obvious that the number of new plants which could thus be created is without limit. Hybrid rhododendrons will not reproduce themselves true from their own seed and so must be propagated by cuttings or grafting. While a few of the native species rank in every way with the best of the hybrids, generally speaking, the painstaking work of the hybridizers is revealed in the superior quality of the new hybrid varieties.
The Rhododendron Association and the Royal Horticulture Society of England have performed remarkable service to horticulture by publishing descriptions of all these known species and hybrids.
Origin of Native Species
Rhododendrons and azaleas, which are included with the rhododendron family, are no doubt the most outstanding group of flowering shrubs in the world. In North America there are only 17 native species, in Europe there are 4 and in the Arctic region 2. In the Caucasus Mountains there are several species, and in the Himalayan Mountain region of Asia the number of species totals nearly a thousand. North India, Burma and Western China are the great rhododendron districts of the world. There are few rhododendrons south of the equator.
Rhododendrons, like other plants, respond to care, and they especially cherish good soil, fertilizer, moisture, and afternoon shade. It is doubtful that any other group of flowering plants will give so much beauty with such a minimum of care.
Various Types Found
Plant explorers tell how whole mountainsides in the Himalayas are covered with creeping rhododendrons which are a mass of color in blooming time. These consist of a number of varieties, viz: R. repens (bright red), R. radicans (purple) and R. forrestii, which are of exquisite beauty. These species are growing on the Pacific Coast and are ideally suited for transplanting to some of our mountain gorges and parks.
There are the miniature leaved Lapponicums, with their dwarf growth arid varied colors of purple, yellow, pink, red, and white. There are the R. Triflorums, medium sized shrubs with bright colored leaves and which cover themselves with brilliant blooms of blue, purple, rose, or white; the yellow R. campylocarpums with their various shades of yellow bells: the R. thomsonii, and the R. arboreum species with their blood red blooms - all are never to be forgotten sights when seen in bloom.
There are tree rhododendrons, which grow to heights of 20, 30 and 40 feet, or even up to 80 feet; most of them are very hardy and some are rated with four stars by the British Rhododendron Society. They have color to suit the most discriminating taste, including deep reds and maroons to fiery scarlets; pinks of all shades; all shades of yellows, orange and copper tints; purples, blues or various tints with markings of gold.
A Fascinating Hobby
Collecting rhododendrons is a hobby which provides a never ending challenge as there are so many species to be acquired and so many magnificent new hybrids being developed. What a thrill to see a new specie budded or to watch a new hybrid never seen before in this part of the country burst into bloom in all its glory' If you want a stimulating hobby that is uplifting and beautiful, one that will never grow old in all seasons of the year, and one that will increase in interest as the years go by, then grow rhododendrons.