Fir is an evergreen conifer that is widespread in the forests of the Northern Hemisphere and often used as an ornamental tree. In nature it can reach impressive dimensions, but it is also frequently used for the formation of bonsai.

The fir family is very large and includes several genera and species, separable in Abeis and Picea. Both are characterized by small 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, white fir bonsai (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 smooth silvery-white 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 edges and a rounded non-pungent tip, are arranged in a double comb in regular ramifications.The spruce is characterized by a resinous and thin bark with a reddish color that becomes brown-greyish in the adult specimens, a sharp top and a conical and narrow crown, pyramidal in shape and dark green. The upper branch is ascending, while the lower one is horizontal or hanging; the leaves are made up of pointed quadrangular section needles.

Although the fir is a widespread species in areas characterized by a harsh climate, a lot of attention must be paid to the exposure and care of the bonsai fir. It needs a very bright position, so it is identified as an outdoor bonsai and requires exposure to the open air, with some fundamental precautions: in the winter months, it is good to protect the plant from frost, covering the pot and the roots; in early spring it is necessary to take special care of watering, to avoid stress caused by abrupt climate change; in the warm months it is advisable to place the plant in a shaded and ventilated area, to avoid excessive drying of the soil.

The Spruce bonsai does not tolerate water stagnation, therefore it is a good idea to wait for the soil to dry evenly between one watering and the next. The operation must also be performed slowly, pouring water directly on the ground without wetting the plant, and the frequency of irrigation must vary according to the climatic season: if frosts are forecast in winter, it is recommended to postpone the intervention or carry it out in the hottest hours; in the warm months, on the other hand, the foliage should be vaporized with distilled water and frequent watering, preferably early in the morning or late in the evening.To restore the nutrients of the soil and stimulate rooting, during the growing season, which runs from April to the beginning of July, it is necessary to administer liquid organic fertilizer every ten to fifteen days, diluting it in the watering water.

The repotting operation must be performed at the beginning or at the end of the vegetative season, therefore at the arrival of spring or late autumn, but the Bonsai fir has no particular soil needs, as long as the substrate is porous and the soil consists of peat, sand and clay with a prevalence of sand. The operation must be repeated every two years in young specimens, every four-five years in adult specimens, remembering not to expose the plant to the sun immediately after repotting.

The formation of the bonsai fir must be scrupulously cared for and controlled to avoid the development of a poor and irregular branching. Formation pruning should be performed in the period of vegetative stasis (from autumn to the end of winter), when the plant loses less sap, trying to give the bonsai a triangular profile and evenly thin out the foliage. Larger wounds must be promptly treated with healing mastic, a substance that also helps to create a barrier to any parasites. During the vegetative season, to avoid a confused mass of new shoots, it is good to apply a careful selection, lightening the areas that are too thick and eliminating the buds facing too much upwards or downwards. Throughout the year it is possible to carry out maintenance interventions, taking care to clean up the foliage from 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 cared for properly. The most frequent diseases are caused by rusts, fungi, woolly aphids, mites, red spider and cochineal, and can cause yellowing or partial fall of the leaves. It is therefore recommended to carry out preventive treatments a couple of times a year, for example by administering jin liquid or sprinkling pine oil on the foliage. In the event of pathologies occurring, it is recommended to act promptly, combining the use of a fungicidal and germicidal solution with the manual removal of encrustations.