Any woody plant whose parts are in proper proportion for dwarfing—and particularly, any that shows promise of interesting lines or “character”—is a good prospect for bonsai. The coniferous evergreens are most popular, because they hold their foliage all year, and because small-needled types are comparatively plentiful. Small-leaved deciduous trees can be at their most attractive best with spring’s budding new growth, summer’s airy foliage, fall’s brilliant color, or with the silhouette of a naked trunk in winter.
With flowering trees and shrubs the choice of varieties narrows even more. Large flowers with brilliant color and overpowering fragrance may destroy balance and proportion, and detract from the beauty of the plant itself. More delicate plants are more likely to enhance the picture. For obvious reasons, plants that bear fruits and berries in the proper scale are the hardest to find, and culturally the most difficult.
(For plants that are suitable for outdoor bonsai, see list at the end of Chapter 14.)
Sources
Bonsai becomes a reality faster, of course, when you start with a fairly mature plant. The most fruitful source is the selection of three-year-old trees and shrubs at your local nursery. Those growing in gallon-sized cans, or other containers, naturally accept pruning and transplanting with the least setback. They should be healthy plants, not overgrown or neglected, that have been regularly root-pruned and transplanted through their infancy. It is perfectly safe to buy them pot-bound if that condition has not persisted for several seasons, with the outer roots all dead as a result.
In selecting a specimen, first examine varieties that are by nature slow-growing and have leaves, or needles, in perfect scale. Be selective, pass up the symmetrical specimens that are best for ordinary landscaping purposes, and look for that one plant in a thousand, the one with interesting “character”—peculiarity of shape, irregular branches, low horizontal growth, stocky or twisted trunk. The most ideal plant has its largest branch near the base, and has no regular or opposite branches to be pruned away. Next to above-ground development in importance, is the below-ground root system. To be ideal, the root system should be a compact, shallow mass rather than one long taproot with a few offshoots. To make it even more ideal, the stoutest roots should be growing near the surface.
Younger, smaller bonsai plants are readily available from mail-order suppliers who specialize in them. Here, make your selection according to variety, and then train your plants as you grow them. But beware of cheap “bargain offers.” I speak with this advice because of the experience of some of my friends. They were too intrigued by Sunday-newspaper ads. Buy only from reliable growers who have invested time and care in developing healthy plants and, better yet, have labeled them true to name. For those who are more interested in the finished work of art than in the growing and creating of it, some florists and nurseries advertise mature, or nearly mature, bonsai. Again may I say, “Beware.” The supplier’s reliability is even more important.
Sometimes you can find precious bonsai-type shrubs or trees growing in the wild. Small seedlings of hemlock, ash, birch, maple, and some elms, if they are dug very carefully—and at just about any time of the year—can be used as miniature bonsai, or they can be planted in the garden for a few years until they are larger. Usually, the taproot has to be cut back rather severely to encourage the development of a spreading mass of smaller roots. Start your regular pruning as soon as the plant recovers from transplanting shock.
The larger native plants should be taken when they are dormant, in late fall or the earliest spring. In searching, look for those that have been naturally dwarfed and misshapen by misfortune. In digging, make sure the soil is so moist that much of it will cling to the roots. Keep the roots moist and well covered against drying sun and winds until the transplant is safely in the soil again. For any such wildlings, take along enough of the surrounding soil to fill the container into which they are going. This will make them feel at home in their new place in the garden bed.
Many growers now propagate their own bonsai plants; thus they can control shape, root-spread, line, and design from the very beginning. Almost all of the propagating methods outlined in Chapter 10 are useful here, some especially so. Cuttings of all kinds will produce stout-trunked plants much faster than seeds. Plants such as willow, holly, ginkgo, and ivy can be started from stems as thick as an inch or so in diameter. With cuttings you can have quantities of new plants from one parent, all with the same variegations or other characteristics.