Bonsai enthusiasts often choose conifer specimens to produce their works of art; in fact there are hundreds of species and varieties of conifers, most of which are very rustic and resistant, thus laying a good basis for an outdoor bonsai, without major problems with cold in winter or with summer heat.
Furthermore, the presence of minute foliage, such as the scales or needles of many conifers, allows to obtain a bonsai with small leaves already when the plant is young; for this reason varieties with particularly small leaves are often chosen, such as some species of juniper or cypress, so as not to worry too much about the appearance of the leaves.
In fact, however, to obtain a harmonious and well developed conifer bonsai it is necessary to give the plant a lot of special care, for several years, in order to obtain those specimens with an ancient appearance; very often on the trunk of coniferous bonsai is also practiced the jin, that is the stripping and lightening of some stumps of branches, in order to simulate a roto branch from the weather, or also the shari, the barking and lightening of a part of the trunk: these techniques, for which many conifers with very light wood lend themselves well, simulate nature, given that many conifers are subjected to bad weather, such as frost, snow and wind, which even in nature cause ruined plants with broken branches.
Which conifer to choose
There are hundreds of species of conifers, belonging to various families, and thousands of varieties have been derived from them over the years. Many species are definitely very vigorous, and it is very difficult to contain the exuberance to produce a bonsai.
Beginners who want to try their hand at a conifer bonsai often choose the new garden varieties, those that even if planted in the ground would not give rise to a tall tree, but to a small, slow-growing shrub; in this way the bonsai obtained however tends to be minute and small, even if the cures are not exactly perfect.
Even in supermarkets it is now possible to find very small conifers, of varieties that at most grow up to 70-80 cm, which act as a good exercise for those who later want to try their hand at conifers with the most common development.
Many novice bonsai enthusiasts soon arrive at a conifer, partly because the pruning techniques are particular, and can only be learned by cultivating a conifer; partly because they are rustic plants, which also bear some slight neglect; but also because conifers are generally not very expensive plants, and sometimes it is possible to buy a plant from which to obtain a pre-bonsai without investing significant amounts, thus avoiding despair in case of failure.
Pines, firs, larches and yews are certainly conifers suitable for expert bonsai lovers, as care must be taken to keep the crown compact, the short branches and the minute leaves.
Certainly the most appreciated species, also typical in the homeland of bonsai, is the pinus pentaphylla, a majestic tree, which gives rise to resistant and long-lived bonsai.
Most of the pine species are used to create bonsai, as well as fir and larch varieties; among the other conifers much loved as bonsai we certainly include the yews, and then junipers, tsuga and cypresses of all kinds, with the foliage of the most varied colors, from gray-blue to yellow-green.
Conifers are completely rustic plants, which can and must remain outdoors for the whole year, even in case of frost, snow or other bad weather; they prefer sunny locations, but remember that in most cases they are alpine plants, and therefore do not like the summer heat too much: therefore in summer we remember to shade them, or to increase the ambient humidity, especially if we live in the south.
They adapt very well even in case of not ideal climate, being vigorous plants, which can bear some neglect, such as a short period of drought, or some excessive watering; however, we must certainly remember that the older the plant and the more resistant it is, care for young specimens must be assiduous, to avoid dry branches or rot.
Obviously, if we want to grow a bonsai conifer, it is essential to know its species and variety, and to remember that the bonsai versions of large trees do not always behave like non-bonsai specimens placed in the ground; so let's avoid leaving our young bonsai conifer completely in disarray, prey to very intense frosts or extreme drought: let's place it outdoors, but in a fairly sheltered place, with a few hours of direct sun a day, but avoiding that in late July it remains at mid-day sun.
The small pot will force us to water fairly regularly, in order to keep the soil, which must be fresh and very well drained, quite humid; in summer, even the vaporization of the foliage with demineralized water should be frequent and regular, to increase the ambient humidity around the plant.
Pruning on bonsai conifers is practiced between the end of autumn and the beginning of winter; remember that these plants, although evergreen, during the cold months go through a period of vegetative rest, during which it is possible to prune their branches and roots, and repot them if necessary.
To keep the size of the needles or the tips of the branches in cypresses contained, it is important to pinch the shoots; this practice is practiced throughout the year, particularly in spring, when the young shoots are more numerous. The pinching consists in the shortening of about half of all the leaves that develop in the young shoots; as regards junipers, tsughe, cypresses, and any conifer that has scales, pinching is done by removing the apex of small newly developed branches, shortening the central branch and also the 2-4 branches below.
The best tool to practice this operation are our fingers, because in this way we can control the pressure exerted on the leaves, avoiding crushing the part that will remain on the tree, still in vegetation.
Said like this it seems a simple operation, and in fact it is, only that, especially with regard to prebonsai and young specimens, it is a practice that takes us for a long time, and frequently: to "clean up" a small young cypress we can also take an hour to pinch the spring shoots.
Despite taking a long time, it is a fundamental practice, which must be carried out continuously, throughout the vegetative development period of the plant. The pinching allows to obtain, over the years, conifers with small foliage, very compact and well developed.
Coniferous bonsai: Pests and diseases
Even if they are rustic plants, let's not forget that bonsai cultivation involves slightly greater demands than cultivation in the open ground; for this reason often coniferous bonsai, and in general all outdoor bonsai, often dry out due to total neglect: if it is true that our spruce in the garden for years has no longer required care, let us remember that the bonsai specimen obtained from its seeds will need care even when they are 100 years old. So even if they are quite vigorous and resistant bonsai, we avoid leaving them without water for months, or in full sun in summer, some simple care will allow us to grow our bonsai plant for years.
Generally the parasites that most often attack the conifers are the aphids of the cypress; these are small aphids that normally also attack conifers grown in the ground, the color is often identical to that of the foliage, and they hide on the back of the leaves, or at the base of the same, so as not to allow us to notice them. The presence of aphids on conifers in the garden often does not cause serious damage, and therefore we hardly care, or even hardly notice them. On bonsai, however, these small insects can cause even serious damage, with loss of the tips of the branches due to desiccation, or yellowing of part of the foliage. A timely treatment, to be practiced in early spring, with a good pyrethroid or with imidacloprid-based products, may be sufficient to prevent the reappearance of small insects.
A very dry climate can cause the appearance of scale insects, especially in summer or in specimens that in winter are crammed into a cold greenhouse, with little or no ventilation; a late winter treatment with white oil should avoid the presence of cochineal, which, moreover, is unlikely to settle on plants grown in a well ventilated place with the right humidity.