Situation, Position and Placement
Most species of bonsai can quite happily tolerate full sun and will thrive in this situation. A light position is essential for good budding and healthy, compact growth. If kept in a shady area, the leaves can get larger with growth quickly becoming leggy and sparse.
It is important to realise that bonsai soon become accustomed to their environment and with this in mind, in late spring should be sited in the position where they will remain for the summer. Hornbeams and maples are often mistakenly believed to be shade lovers and if exposed to full sunlight from spring, will grow happily and strongly. However, if grown in heavy shade and then suddenly moved into a position where they will receive strong sunlight, scorching of the leaves is almost inevitable.
Bonsai trees are best viewed at eye level and well spaced out so that their structure and form can be easily appreciated. Keeping them off the ground also helps to deter some pests and by not overcrowding them, allows maximum light for growth. Rotate the trees regularly so that the back and sides benefit from an equal amount of light. It is easy to enjoy a tree from the front, without realising that the back is suffering and beginning to die back through lack of light.
The foliage of trees growing in good light will often be lighter in colour to that of trees growing in heavy shade, because the leaves are working so efficiently. When growing in shade, the foliage turns darker to absorb more sunlight. This is useful when preparing trees for exhibition, as by placing the chosen bonsai in shade for a few days the leaves or needles will often become a much richer green colour. However, this does not apply to trees with copper colour leaves, which start to turn green if positioned in shade.
Most of my bonsai are sited in positions in the garden where they receive maximum light, with the exception of Zelkovas and Willows. I have found by experience that these species prefer slight shade and grow better when kept out of strong sun.