Although all trees, or almost all, can be developed as bonsaï, some species are more suited than others.
In theory there are no trees specifically grown by bonsaï lovers, but varieties with small leaves, flowers, and fruit are usually preferred. Among these, there are three main categories.
Rustic species are preferred for growing outdoors. The most common of these are the Japanese white pine, the trident maple, the field maple, the alder, the European barberry, the box tree, the common hornbeam, the cedar, the cyprus and false cyprus, the hawthorn, the spindle, the ash, the ginkgo, the Japanese holly tree, the juniper tree, the crape myrtle, the larch, the Common Privat, the American Sweetgum, the honeysuckle, the crab apple tree, the redwood tree, the olive tree, the vine, the pine, the cinquefoil, the Chinese quince, the firethorn tree, the pomegranate, the English and the cork oak, the yew, the Chinese, Siberian, caucasian or small-leaved elm, the wisteria and the Japanese zelkova.
The orange grove species
Like their rustic cousins, the orange grove species need to be protected from severe winter frost. The most common of these are the Bougainvillea, the sacred bamboo tree, the snowrose, or the rhododendron.
The more fragile species, especially tropical tres, must be kept in a warm place, with a temperature not exceeding 10°C.. The most common of these are the Jade plant, the carmona, the tropical fig tree and other varieties of fig.
As every species has different needs, it is highly recommended to ask the advice of specialists concerning the treatment of these trees. The main differences of treatment concern the proportion and frequency of watering, the amount of exposure to the sun and their resistance to frost.
Local rustic species generally tolerate severe frost if the pot is suffucienty protected from this. Tropical species commonly sold are logically more fragile. They need to be kept in a cool place in winter, which must also have plenty of sunlight and a stable humidity level. If you don’t have a place like this (a veranda, a glass roof, a greeenhouse) it is advised to grow outdoor rustic bonsaïs.