Poor bonsai

Question: Bonsai delicate

Hi, I have a problem, I bought a zelkova bonsai some three or four months ago, up to a week ago, it was in full force, then it started losing its leaves. I thought that maybe I had forgotten to give her water, and I started being very careful about her watering. But nothing has not been revived and continues to lose leaves (which fade and sometimes even fall green). I also thought about reducing the exposure but nothing, I also applied all the procedures on the internet, repotting excluded. Did I also try to give her water by making her slip from the trunk downwards, that she was wrong? if I have to do a repotting, do I have to do it in a bigger vase? or always the same?

Answer: Poor bonsai

Gentile Luciano,
the name zelkova seems very exotic and seems to indicate a plant with distant origins, in fact it is a plant widely used to prepare bonsai, given that it is a tree of Asian origin, very common in China; it is also commonly called Chinese elm, as it is closely related to the European elm, although it naturally has slightly smaller leaves.
As with elm, zelkova also loses its foliage in autumn, and should have only fresh and tender shoots of new leaves in spring; in fact the zelkova nire (the species most used as bonsai), is a semi-evergreen plain, therefore with a suitable climate it keeps the leaves, if the climate becomes too rigid or dry it loses them, even completely. Just like elm, zelkova can also be an outdoor bonsai, although, in very cold and cold winters, with constant frosts, it is usually grown indoors, or in a sheltered place; in any case it is a widespread tree in areas with winters that are decidedly milder than the Italian ones, therefore, except in those cases where people live in Sicily, the zelkova is grown as an indoor bonsai. In any case, a slightly heated area is sought, with a cool climate and moist air; often a stairwell is chosen, for example, where temperatures do not fall below 12-15 ° C.
Because the main problem when moving outdoor plants in the home, it is always humidity; but not the humidity of the soil in the vase, but rather the humidity of the air; because, even the evergreen plants have a period of semi vegetative rest, during which they do not need excessive watering or fertilizing, which will start again in March-April; the problem is generally due to a lack of water in the air, caused by heating, air conditioning, proximity to a heater.
So probably your plant has received excessive watering but little water in the air; so wait for the soil to dry before watering, which means that in winter you will water only sporadically, while in July you'll water about every two days; in addition to this, add frequent vaporization to the foliage, in order to increase the environmental humidity.
In general the bonsai that are found in the nursery are already completely bonsai, or rather they have already some years of life and a radical apparatus already reduced; when we repot them we prune the roots and change all the soil, but we don't put them in a bigger pot.