When choosing trees to plant in small gardens, it is best to make sure that they will not reach more than about 6 m (20 ft) in height when fully grown. Trees that are prickly or heavily thorned such as hollies (Ilex) or hawthorns (Crataegus) are usually unsuitable for small gardens as they may restrict access around them. You should also avoid trees such as limes (Tilia) that drip sticky honeydew, especially near seating areas.

You may only have enough room for a single, specimen tree; in this case, try to ensure that you choose one that provides interest in more than one season. For example, paper-bark maple (Acer griseum) is a small, slow-growing tree with a good shape, small green flowers, crimson or red autumn colour, and a warm red or chestnut coloured peeling bark that glows attractively in late winter sunshine. The Japanese crab apple (Malus floribunda) provides a profusion of crimson flower buds opening to white or pale blush in April or May. These are followed in autumn by small red and yellow crab apples on arching branches.

If you decide to plant a deciduous tree, take its leafless appearance into consideration, as it may be bare for six months of the year. For example, the weeping silver pear (Pyrus salicifolia 'Pendula') is an extremely elegant tree which forms a dense mound of weeping branches. These are initially clothed with silver grey, downy, willow-like leaves, which change to grey-green in summer. Its branches form an attractive silhouette over the winter months.