A_137 - If you have plants or trees nearby that only flower once every few years and you are not sure of the presence of pollinating insects in the area (for example if you have a cactus and live in the city) I can advise you, in case the plant or the tree carries out its rare flowering, to use pollen (purchasable in herbalists) to try to carry out pollination. It is possible to mix the pollen with water and spray it on the flower, or use a brush or a cotton swab and spread it on the top of the pistils. This will benefit the life of the plant. In certain cases, for certain very tall trees (e.g. baobabs), it may be necessary to use a drone to pollinate them.