Miniature Trees and Shrubs
Another very pleasing and decorative way of having plants indoors is to grow miniature trees and shrubs. They are all fascinating and, as will be discussed later, can give people, who are interested in gardening but have no or little garden, a very absorbing hobby.
The dwarf trees and shrubs that are grown indoors fall into two categories. These are firstly the naturally diminutive ones and, secondly, the artificially dwarfed ones or 'Bonsai'.
Natural Miniatures
It is of interest to discuss for a short time the reasons why dwarf varieties of various species are found growing in nature, because they have some practical bearing on the production of bonsai. Mention should first be made, however, of two other sources of naturally raised miniatures. Firstly, some are obtained by selection of any seedlings that show exceptional dwarf characteristics and secondly, by taking cuttings from 'Witches Brooms' which are dense clumps of stunted twigs appearing on the branches of normal trees and caused by the action of certain insects.
The majority of dwarf trees and shrubs have originated in mountainous and very exposed areas, in which there is poor, shallow soil. This has possibly restricted the growth of their roots, since they are contained by large stones, and high winds and general exposure naturally prune their branches and mould them into strange shapes. They have, under these circumstances, adapted themselves in such ways that they are well equipped to resist adversity. At the same time it should be noted that such plants grow in well-drained soil and are exposed to a great deal of very clean, bright light and to rather cooler conditions; these factors are all useful clues to their cultivation when indoors.
Most miniature trees, whether natural or bonsai, grow best in shallow containers, not only because such a condition is much nearer to that of their habitats, but also because they look more artistic when planted in this way. Good drainage must be assured with ample drainage holes in their pots. If it is desired to plant the dwarfs in ornamental containers which have no drain holes, a good layer of ballast or crocks should be put at the bottom. The addition of a few lumps of charcoal is also an advantage as it helps to minimize sourness.
A good soil, although not too rich, is the best in which to plant the natural dwarfs. Bonsai, however, require an even poorer soil if they are to retain their diminutive stature and they grow better in a mixture of two parts commercial potting compost and one part coarse sand. They require regular watering, but no feeding because this encourages unwanted growth.
Regarding the selection of natural miniature trees and shrubs, the most fruitful source is the dwarf conifers. Among them, there are some most fascinating, shapely, colourful species and varieties; in particular those classified as real pygmies prove delightful for indoor decoration. Anybody interested is advised to pay a visit to one of the specialist nurserymen in the country in order to make their own selection. A few good selections are white variegated, columnar Cha-maecyparis lawsoniana 'Ellwood's White', C. pisifera 'Nana', which is a tight, low bun of dark green foliage, C. pisifera 'Nana Aureo Variegata', which has a superb golden sheen, C. pisifera 'Plumoso Compressa' which is a perfect gem for a pot, Cryptomeria japonica 'Bandai-sugi' which has dense moss-like foliage, grey-leaved, columnar funiperus communis 'Com-pressa', the globose, blue-foliaged Picea mariana 'Nana', the dwarf yew, Taxus baccata 'Nutans', Thuja occidentalis 'Hetz Midget' which is one of the smallest of all conifers and T. orientalis 'Minima', which is exceptionally neat, slow-growing and globose in shape.
Regarding shrubs, the purple Acer palmatum 'Dissectum purpureum' and its green counterpart A. palmatum 'Dissectum viridis' have been found to be elegant small trees, lasting for many years. Miniature roses, of which there are many varieties, have also been successful. Other attractive dwarf plants that can be seen at leading nurseries are: very dwarf Cotoneaster dammeri, evergreen Daphne collina, with deep bluish-green leaves and soft purple flowers, evergreen Pernettya tasmanica, which only grows two inches tall and has red berries, and Santolina chamaecyparissus 'Nana', which has the most distinctive, white, frosted foliage.
Artificially Dwarfed Trees and Shrubs or 'Bonsai'
The bonsai art, which has been practised in Japan and China for many centuries, is well established in the United States and is becoming steadily increasingly popular in Great Britain. For those whose sole interest in miniature trees is for interior decoration, for which they are most valuable assets, it is possible to buy specimens from florists and specialist nurserymen, and to plant them in specially chosen containers, but some of the larger and very old ones can cost several hundreds of pounds. Dwarfing trees and shrubs can, however, be a most absorbing hobby for both young and old, not only because it is a form of horticultural and artistic interest, but because if it is practised faithfully, it involves the study of the habits of various trees. It is indeed a vast subject and can only be briefly touched upon in this book, but because it is of importance, a short description of the process of producing bonsai is given.
Quite a number of both native and exotic trees and shrubs are responsive to this treatment. In fact, after some experience has been gained, it is worth while trying out any particular favourite. As a preliminary, it might be mentioned that generally plants with small leaves and flowers give dwarfs of good proportion and thus have a correct appearance. An exception to this assertion is that flowers growing in racemes, like those of wistaria and laburnum, are always most attractive. Another factor to be taken into account is that large flowers are not reduced in size.
Centrally-heated, modern rooms with plenty of light make it possible to grow half-hardy dwarf plants such as oleanders and olives, indoors in a sunny window. All bonsai must, however, be kept out of draughts and away from the fire. Spraying with water at room temperature once a week and sponging the leaves occasionally to remove the dust is also appreciated. The hardy dwarfs should also be put out of doors in warm rain as often as possible.
The Dwarfing Process
Trees and shrubs, of which a selection is given below, are started from cuttings or seeds or seedlings found in the garden by planting them in a shallow pan in potting or seed compost. The seeds should be soaked in water for twenty-four hours. The larger ones, such as acorns and beech nuts, should be placed about half an inch down, but smaller seeds less deeply. The pan should be well watered before planting and kept continuously moist. When the cuttings are rooted and the seedlings are two inches high, the dwarfing processes, which are spread over two years, or three in the case of very slow-growing plants, are started. The little plants are transplanted to individual containers, using a commercial potting compost. These can be clay or plastic pots with ample drainage holes. If these are used, during the next two years, the young plants are periodically removed and all the roots growing outside the ball are cut back. As an alternative, they may be planted in cream or ice-cream cartons, in which holes have been punched in the wall and bottom with a knitting needle. As soon as the roots protrude through the holes, they are cut off. Some growers prefer, as a third alternative, to plant out in the skin of half an orange or grapefruit, which is soft enough to allow the roots to pass through, and then be clipped off.
This process of root pruning continues during the plant's second year, during which time steps are also taken to shape the plant. This is done by pinching out the growing tip with the finger and thumb to encourage it to grow bushy. After this, it is shaped by shortening the shoots one after another and removing completely any undesirable ones. In order to minimize shock, root and shoot pruning should not be carried out simultaneously. Shoot pruning should be aimed at giving a natural outline to the dwarf, similar to that which the large tree would take up on maturity. This process, which must be spread over a continuous period, is best done in spring and summer when growth is at its greatest.
Sometimes it is desired, as the Japanese do, to give the miniature the appearance of premature old age or, perhaps, grotesqueness. This is done by mechanical means, such as curling wire round the branches and trunk, so bending the tree to shape, fixing weights to branches to bear them down and twisting the trunk antl limbs by tying them to pegs firmly inserted in the soil.
At the beginning of the third year, after root pruning, the bonsai should be transferred to their permanent quarters in poor soil, composed of two parts potting compost and one part coarse sand. During this year the plants should be pinched back from time to time to regulate their appearance.
Among the plants readily dwarfed artificially are the conifers, abies (firs), monkey-puzzle tree, chamaecyparis, cedars, gingkos, hemlock spruce, junipers, larch, pines, spruce and yews; the suitable evergreen and deciduous trees and shrubs include acacia (including mimosa), beech, birch, buddleia, colutea, crab apples, deutzia, dogwoods (cornus), eucalyptus, hawthorns, holly, horse chestnut, ivies, jacaranda, laburnum, lilac, maples, oleander, olive, philadelphus (mock orange), poplar, primus (viz. flowering almonds, apricots, cherries, peaches and plums), pyrus, pyracantha, snowberry tree, tamarix, walnut, willows, winter sweet and wistaria. |
