Stuartia pseudocamellia is a very special tree with camellia like flowers in summer, and wonderful autumn displays.
Acer shirasawnum 'Aureum'
For those with cool climate gardens wanting foliage colour on a small tree, Enkianthus campanulatus will delight with its intense colours. The sharper the evenings and brighter the days, the deeper the bronze foliage becomes.
The dogwood (Cornus ssp.) family put on a final display of brilliant red and orange-gold before retiring for the winter. Cornus nuttallii will colour bright red before the leaves fall. And the spindle berry, Euonymous alatus and E. europaeus, not only produces its curious 'spindle' like fruits but has foliage in intense glowing red that really stands out in the garden. There are a number of named cultivars available, with particularly intense colours.
Spindle berries, Euonymus europaeus
Fraxinus angustifolia 'Raywood'
the Claret Ash
The witch hazels (Hamamelis) burst into brilliant colour in autumn, an extra contribution as a prelude to their winter flowers. Look for varieties that have good autumn colour as well as the lovely, fragrant winter flowers.
Crab apples and cherries will turn orange and gold in autumn, adding another season of interest to their role in the garden. Prunus 'Pink Perfection' has yellow autumn leaves; 'Shirofugen', 'Ukon' and 'Shimidsu Sakura' also have good autumn colours (see feature on Flowering Cherries for more)
Amelanchiers (Amelanchier canadensis and A. lamarckii) contribute creamy white blossom to the spring garden and the copper foliage in summer is an asset as part of your overall scheme. They are an impressive sight in autumn; their coppery leaves turning a deep red before falling.
The ash will also bring brilliant colour into your garden. The claret ash, Fraxinus oxycarpa 'Raywoodii' turns from deep green to a deep, brilliant purple-red while F. excelsior glows a wonderful mellow yellow. The ash, however, is for larger gardens as it becomes quite large and is inhospitable - few plants can survive in the dense mat of roots and dry shade under its canopy.
Birches are also poor neighbours with a dense mat of roots bullying other plants that strive for an existence beneath or near them, although they are undeniably lovely and widely planted. The silver birch (Betula pendula) is striking in the autumn with its silvery trunk against the glow of gold and yellow leaves. Other birches worth trying are B. jacquemontii and B. papyrifera. Group them, if you have room, to make a feature of their white stems in winter.
Quercus coccinea and Q. rubra, the scarlet and red oaks, are a wonderful mass of red foliage each autumn. They are, however, forest trees and suitable only for the larger garden and not for your courtyard! Smaller and faster growing, Q. paulstris, the pin oak, provides brilliant autumn colour and has an attractive conical shape when young, becoming round headed only with age.
A spectacular tree is Nyssa sylvatica, the tulepo, which has a striking conical shape when young and absolutely stunning autumn colour. Again, at an eventual height of 30m, it needs a larger garden to do it justice. It prefers a moist or damp soil.
Another larger tree that prefers a moist position is the Liquidamber (Liquidamber styraciflua), there are numerous named varieties ('Worplesdon' and 'Lane Roberts' are both good forms) that will give you a range of dependable colour, even in warmer climates.
If you live in a warmer climate and pine for autumn colour there are some trees that provide reliable autumn colour.
The sumach, already mentioned above, and Lirondedron tulipefera, or tulip tree, is butter yellow in autumn. It is very large, in time, so site it carefully. The crape myrtle, Lagerstromeria indica, is another tree that will produce a short but reliable display of golden red foliage in warmer areas.
Certainly, planting for autumn colour gives a lift to the end to the growing season in the garden, a boost of brilliant colour rather than a dismal feeling of winding down and dying.
It is definitely worth getting out and adding autumn colour to your garden.