RHODODENDRONS (Ericaceae)

Travellers to the realms of the Rhododendrons go hand in hand with Gulliver. At one time they wander lost among the giant Brobdingnagians of Burma, tree species 100 ft. high, and in their season, covered with masses of brilliant and enormous flowers; at another they stride valiantly over hosts of Lilliputians, little 6-in. plants that blossom out into a sea of colour on the moorlands of lofty mountains in East China.

Between these extremes lies an immense variety of size, and colour. Every tint from deep purple and lavender blue through all the shades of red, orange and yellow to creamy white is pressed into service, and almost every type of woody-stemmed plant, from the tree to the almost prostrate shrub. Rhododendrons have an independent spirit, however, and refuse to be climbers. Their distribution is as various as their height and colour. Across the whole stretch of Europe and Asia, reaching down through Malaya into Northern Australia and westward across the United States, they are found. Only in South America, Africa and New Zealand are there none.

For convenience in dealing with so unwieldy a mass of varieties, they have been roughly grouped, partly according to districts and partly according to habitats. Dwarf plants belong to Lapponicum, Cephalanthum and Neriflorum series, while the giants are of the Stamineums, and between them come the Fortunei, the lrroratums and the Maddens, etc.

The Ponticumis, originated in Asia Minor, Spain and Portugal, and the deciduous section is largely American.

Characteristics of Rhododendrons

Though mainly evergreens, true winter buds appear. The leaves are smooth edged, leathery, shiny above, sometimes hairy and sometimes scaly underneath, and arranged in rosette form at the ends of the shoots. They are sometimes aromatic.

The flowers are in trusses at the ends of the flower stalks, and are bell or funnel shaped generally, and 5 lobed with 10 stamens. The seeds are small, numerous and winged, and are set free by the splitting of the capsule into five sections.

Massed in great bunches, these loose trusses of flowers, seen in a wood-land glade or on a terraced lawn, are strikingly handsome. Why, then, do we not all grow Rhododendrons in our own gardens?

Soil

The first reason is probably that they are plants of strong likes and dislikes—chalk and lime are their pet abominations, and a soil rich in humus or peat, with a base of sand, is what they require. The second reason is expense.

Moreover, should the poor man decide on seedlings to suit his pocket, he will need much patience—for Rhododendrons do not flower till they are three years old, and may not till they are twenty! At the same time, if one plant is purchased the owner can produce many others, in course of time, by the familiar process of layering—so that the investment is not so unprofitable as it appears at first sight.

For the slender purse, it is well to avoid any varieties of stamineum, arboreum, vaccinoides, Maddeni and brachyanthums. They are difficult to rear, and die more readily.

The old complaint that the flowering period was so short is dying out now that the new hybrids flower younger, and continue their flowering period for so much longer. But at present many of these plants go very shabby all the winter, their leaves curl and look dusty and weather stained. To this some tidy-minded gardeners take exception.

Cultivation

Rhododendrons can be planted in open weather any time from October to May and grow well in good loamy soil with leaf-mould and plenty of sand if no lime is present. They certainly like peat —but can do without it. Sand, however, is very important, as it secures aeration of the soil, and allows for the proper functioning of the bacteria on which the health of the Rhododendron depends.

The more silicate the sand contains, the better for the plants—but there must be no lime or chalk—even the water used must be “soft water.” Shallow planting and firm planting are both essential, and a layer of leaf-mould for the roots to rest on is beneficial. Rhododendron roots are continually coming to the surface, and the grower must remedy this with an annual top dressing of 1 in., not more, of leaf-mould to keep the roots cool and moist, to afford some nourishment, and to keep off ground draughts.

Propagation

Cuttings may be taken in September of the current season’s wood with a heel attached. They should be firmly planted in a frame containing a mixture of 3 parts sand to 1 part leaf-mould. They should be in a sunny part of the garden, but should be kept close and shaded till mid October, when the shade is removed. The cuttings may be sprinkled with water on fine days. The frame is kept close till spring when the cuttings are rooted into richer soil.

Layers may be encouraged—some Rhododendrons root their lower branches naturally—and these may be in twelve months time separated from the parent. This is often a better way for the amateur to increase his stock than by cuttings.

Seeds are a ready means of increase, as well as of hybridization. It is best to sow in granulated peat moss and sand, as there is less damping off, less watering is needed and no weeds grow. The boxes are well and cleanly crocked, the peat moss laid over a compost of sand, loam and leaf-mould, and well pressed down, the seeds sown thinly, and not covered. The boxes are covered with glass, shaded with paper, and, in a month, germination should take place.

A little ventilation, and the turning over of the glass, are then needed. When the second pair of leaves come, a little more raising of the glass is required. In due time the seedlings are pricked out into pans of very sandy soil, and eventually into the open ground.

The majority of Rhododendrons like a position in open sunny borders, or in shrubberies where slight shade relieves the sunlight. Many show to best advantage with a dark background of trees. It is usually a mistake to plant them on a slope, but a grassy terrace sets them off to advantage, and the dwarf kinds make gay little rockery plants.

As soon as the flowers fade, seed pods should be removed; other pruning is not necessary, except in cases of overgrown bushes.

Rhododendrons are singularly free from disease, and the Rhododendron fly, Rhododendron beetle and White fly are seldom very serious, and are easily controlled by fumigation or spraying.

Included in the genus are the Azaleas which differ from other Rhododendrons mainly in the glory of their autumn foliage, which is shed before the frosts. They are also more brilliant in colour than the Rhododendrons.

Linking the two groups are the Azaleodendrons, hardy hybrids, and mainly evergreen, and it is by the judicious mingling of the diflerent groups according to their colour and flowering time that lovers of the Rhododendron can secure a long-continued series of bloom. Amid such a multiplicity of choice, it is advisable to consult the catalogue and the nurseryman if planting in any quantity. For the moderate sized garden, one variety that never seems to fail, in sun or shade, country or town, is Pink Pearl, and for the rock gardener the little dark crimson flowers and low creeping habit of R. Forrestii, one of the Neriflorum series, is perfection. For a more spacious habitat a masterpiece of the breeder’s art is R. Loderi, with deliciously scented shell-pink flowers, each 6 in. across, massed together in trusses of nine or eleven, and making a magnificent natural bouquet.

Pot Plants

The brilliant flowered Azaleas are often grown in the greenhouse for early flowering and are sweet scented. Of these the following can be recommended to the owners of cold greenhouses:

R. auriculatum. R. odorahim. Azalea pontica. A. viscostim.

04. September 2013 by admin
Categories: Fruit Gardening, Kitchen Gardens, Uncategorized, Vegetable Gardening | Tags: , , , , | Comments Off on RHODODENDRONS (Ericaceae)

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