The Cotoneaster is among my all time favourites for shohin-bonsai. especially for Mame-bonsai (from 9,5 cm and down), because it is slightly draught tolerant, and can develop a fine root system for the extremely small pots used.
Cotoneaster × suecicus ‘Coral Beauty’ is one of the varieties among the Cotoneaster specimens that are particularly good for Shohin bonsai. It is a summer flowering specimen, and therefore it sets its flower buds during spring. If you want flowers, you should not prune after the dormant period in winter, when leaves have dropped.
Other (but fewer) varieties are evergreens, as it is the case with the Cotoneaster microphylla. As other types of Cotoneaster it has white flowers followed by red or orange fruits in autumn. C. microphylla is a spring flowering specimen, and therefore it is necessary to stop pruning before fall, when the flower buds for spring are produced. If pruned in autumn/fall, you risk pruning away the small flower buds that are prepared for spring.
Cotoneasters are very tolerant regarding soil types and watering. They also willingly produce a massive amount of new growth when pruned hard. As long as they are fed well and taken care of, this the tree every shohin grower should have in their collection, if the specimen is available in your location. They are found in nature from western China towards Northern Europe.
In midd-summer it is advisable to keep the pot and tree semi shaded during the hot part of the day, were the sun will heat up the soil and roots. In winter keep the tree from freezing in several days, and place it protected from winds (best choice is a greenhouse) because the leaves still will be evaporating trough the leaves, especially if exposed for the sun. Leaves and branches will dry out when the soil is frozen and cant take up water for evaporation.