By the autumn many of the summer-flowering plants are all but over and, although there are many plants which will provide a display of flowers in September and October, and even into early November, much can be done to make the garden colorful in these months by planting some of the shrubs and trees the leaves of which turn brilliant colors before they fall. The intensity of coloring and its duration varies annually, as much seems to depend on the weather.
A mild, calm, but not too dry, autumn following a hot summer may result in a display of color lasting for several weeks, the leaves turning gradually from one shade to another and remaining on the plants for a long time. Conversely, in a wet windy autumn following a dull summer, the leaves may turn quickly, the colors will be less brilliant and the gales may quickly strip much of the foliage from the trees.
However, the gardener should always take the long-term view, particularly when planting such permanent specimens as trees and shrubs. It is worth remembering when making a selection of such plants that many of them will give two or even three seasons of beauty; the first when they flower, then when their leaves turn, and finally when their colorful fruits hang from the leafless twigs, adding their quota of color to a dull scene in late autumn and winter.
The most brilliant autumn leaf colors are found among the Japanese maples (Acres), but, unfortunately, the flowers are insignificant and the fruits, if they are formed, are but smaller replicas of the winged fruits of the common hedge maple. Even so, there is much beauty in the leaves before they turn color for they are often much-lobed, divided into as many as eleven narrow segments, giving the small tree or shrub a delicate, airy appearance.
Among the best of these Japanese maples is Acer palmatum septemlobum osakazuki, the many-lobed leaves of which turn to the fieriest scarlet. Others turn all imaginable shades of crimson, bronze and gold. There is a wide selection, including some which have bronze, crimson or yellow leaves during summer
Amelanchiers can usually be guaranteed to give good autumn foliage color and they have more to offer as they produce attractive trails of white flowers in April, followed by maroon fruits. These, alas, are too attractive to birds to remain on the tree long. The deciduous azaleas are very much two-season plants, colorful in spring when they flower and again in autumn when their leaves turn.
Others of this kind, beautiful in flower and leaf, include a few of the spring-flowering cherries (prunus), the Chinese witch-hazels (hamamelis), the buffalo currant (Ribes aureum) and certain viburnums Among those with handsome fruit as well as worthwhile autumn color are several crabs (malus), viburnums, including the native guelder rose, V. opulus. and mountain ashes (sorbus).
Conifers, on the whole, provide little autumn color. The exceptions are Cryptomeria japonica elegans, a form of the Japanese cedar in which the foliage turns a pleasant reddish-bronze with the approach of winter, resuming its normal green in spring; Ginkgo biloba, the maidenhair tree, the fan-shaped leaves of which turn a good yellow before falling; Metasequoia glyptostroboides, the dawn redwood which turns pinkish-brown, and Taxodium distichum, the swamp cypress, the foliage of which turns bronze-yellow before falling.
For further details of the cultivation and propagation of the trees and shrubs providing autumn color, reference should be made to the entries under trees and shrubs.