good morning I notice in my Chinese elm that some leaves have a black border! What should I do?? Thanks for your attention Lele

Dear Lele,

the Chinese elm, zelkova nire, is a beautiful bonsai, very suitable for beginners, because it produces very small leaves, and is vigorous and hardy. Generally the edge of the leaves which tends to darken is a symptom of problems linked to excess watering; it is not always easy to be able to water bonsai correctly; often there is a tendency to water too little, leaving the little soil in the pot to remain dry for a long time, and the result is dry or withered leaves; if, on the other hand, you water too often it can happen that the bread of earth around the roots always remains completely soaked in water, leading to asphyxiation of the roots, which are no longer able to exchange gaseous with the outside, and with consequent development of fungal parasites . To treat the plant already affected by this problem, it is advisable first of all to allow the soil to dry between two waterings (check with your fingers: if you feel the soil is fresh and wet, postpone watering for at least a day), and practice at least one treatment with a systemic fungicide, that is a product that must be vaporized on the foliage from which it will be absorbed, to enter the plant’s circulation. Often, in addition to the problem of excess watering, this type of pathology develops in plants grown in poorly ventilated areas, with poor air exchange, and poorly lit. Bonsai, in the hottest summer months, tend not to like direct sunlight, especially in the hottest hours of the day, but it is always advisable to place them in bright and well-ventilated areas; in the case of your zelkova, it wouldn’t hurt to get a little direct sunlight, possibly early in the morning. These plants fear intense frost, but if you live in an area where winters have a fairly mild climate, you can think of growing it on the terrace all year round, so that it enjoys a more natural climate; if exposed to the elements then, in autumn and spring, it will receive the correct amount of watering directly from the rains, allowing you not to think in a nagging way about watering. In any case, whether it is outdoors or indoors, when autumn arrives it is best to further reduce watering, wetting the soil only when it appears completely dry. Zelkove love a cool and humid climate, but fear water stagnation, for this reason, watering is to be provided every time the soil is dry, but the foliage is often vaporized, especially in the hot months, or in the case of plants grown in the apartment. Fertilizers (specific for bonsai) are supplied from March to September, every 12-15 days.