The fir is an evergreen coniferous tree widespread in the forests of the northern hemisphere and often used as an ornamental tree. In nature it can reach impressive sizes, but it is also frequently used for the formation of bonsai.
The fir family is very large and includes different genera and species, separable into Abeis and Picea. Both are characterized by minute foliage, a slender silhouette and rapid and regular growth of the trunk, characteristics that make them particularly suitable for the creation of gardens and groves and facilitate the formation and shaping of the bonsai plant. In Italy bonsai of Silver fir (Abies alba), which is the only Abeis that grows spontaneously on our territory, and the spruce (Picea abies), traditionally used as a Christmas tree, are readily available.
The silver fir has a straight stem, a silvery-white smooth bark, a flat top and a dark green pyramidal crown. The needles, evergreen and persistent, are rigid and slightly narrow at the base, have smooth margins and a rounded, non-pungent tip, and are arranged like a double comb in regular branches.
The spruce is characterized by a thin and resinous bark with a reddish color that becomes grayish-brown in the adult specimens, an acute top and a conical and narrow crown, of pyramidal shape and dark green color. The upper branch is ascending, while the lower branch is horizontal or leaning; the leaves are made of needles with a quadrangular section, pointed.
EXPOSURE, WATERING AND FERTILIZATION
Although fir is a widespread species in areas characterized by a harsh climate, it is necessary to pay close attention to the display and care of bonsai fir. It needs a very bright position, so it is identified as an outdoor bonsai and requires exposure to the outdoors, with some fundamental precautions: in the winter months, it is good to protect the plant from frost, covering the vase and the roots; at the beginning of spring it is necessary to take particular care of watering, to avoid the stress caused by the abrupt climate change; in the warm months it is advisable to place the plant in a shaded and ventilated area, to avoid excessive desiccation of the soil.
The Abete bonsai does not tolerate water stagnation, so it is good practice to wait for the soil to dry evenly between one watering and another. The operation must also be performed slowly, pouring the water directly onto the ground without wetting the plant, and the frequency of irrigation must vary according to the weather season: if in winter frosts are anticipated, it is advisable to postpone the intervention or carry it out in the hottest hours; in the warm months, the hair should be sprayed with distilled water and frequent watering, preferably early in the morning or late at night.
To restore soil nutrients and stimulate rooting, during the vegetative season, which runs from April to the beginning of July, it is necessary to administer organic liquid fertilizer every ten to fifteen days, diluting it in the water used for watering.
RENEWAL AND PRUNING
The repotting procedure must be performed at the beginning or at the end of the vegetative season, therefore at the onset of spring or late autumn, but the Bonsai Spruce has no particular soil requirements, provided that the substrate is porous and the soil consists of peat, sand and clay with a prevalence of sand. The operation should be repeated every two years in young specimens, every four to five years in adult specimens, remembering not to expose the plant to the sun immediately after repotting.
The formation of the Bonsai Spruce must be scrupulously treated and controlled to avoid the development of a poor and irregular branching. The training pruning must be performed during the period of vegetative stagnation (from autumn to the end of winter), when the plant loses less lymph, trying to give the bonsai a triangular profile and to evenly trim the foliage. Larger wounds must be treated promptly with healing mastic, a substance that also helps to create a barrier to pests. During the vegetative season, to avoid a confused mass of new shoots, it is good to apply an accurate selection, lightening the areas that are too thick and eliminating the gems turned too much upwards or downwards. Throughout the year it is possible to carry out maintenance interventions, providing to clean the hair from the broken branches.
Fir is a resistant and robust plant that is rarely attacked by animal and vegetable parasites, however the onset of pathologies is possible if the bonsai is neglected or not properly cared for. The most frequent diseases are caused by rusts, fungi, aphids, lanigeri, mites, red spider and cochineal, and can cause yellowing or partial fall of the leaves. It is therefore recommended to perform preventive treatments a couple of times a year, for example by administering liquid jin or spraying pine oil on the foliage. In case of pathologies, it is advisable to act promptly, combining the use of a fungicidal and germicidal solution with manual removal of scale.