Trees, shrubs, and vines are basic plants for the container garden. They provide height and background, accent, and shade. Since nurserymen and garden centers offer them in bushel baskets, large tin cans or simply balled and burlapped, they are easily planted in permanent containers. Growing trees and shrubs in tubs and boxes is a widespread practice in climates with scant rainfall, like our Southwest and the Mediterranean countries, but gardeners everywhere can treat them as specimen plants. They lend distinction and grace to the large terrace or outdoor sitting area and are effective at doorways, along walks, on driveways, on terraces, and around swimming pools.
One great advantage of containers for trees and shrubs is that you can experiment with kinds that are tender in your climate. Oleanders, lemons, oranges, Chinese hibiscus, and camellias are all possibilities for northern gardeners. Unusual varieties of these and others can be tried, and you can give special attention to rare kinds.
Value of Trees
Trees contribute the element of height and the structural beauty of their trunks and lower branches, especially in winter, if they are deciduous. Some like stewartia and eucalyptus have colorful exfoliating barks that give winter interest. Trees also cast shade for sitting areas as well as for plants and create fascinating shadows on pavements and walls.
As a rule, small foliage or flowering trees-Japanese maples, crab-apples, Oriental cherries, and dogwoods-are best, since they require infrequent repotting. Slow growers, tupelo and ginkgo, are also valuable because they remain useful for long periods. Yet even large trees can be grown successfully in containers. Garden centers carry Norway and Crimson King maples, lindens, oaks, yellow-wood, plane trees, and honey-locusts. When the trees get too large, transplant them to the garden or give them away.
Value of Shrubs
Shrubs are easier to handle because they are smaller and require less space. For mass effects and backgrounds,
rely on large kinds, either hardy or tender, the latter for an exotic touch. Nowadays, shrubs, like trees, can be planted at any time because they are available in boxes, tins, or bushel baskets. This makes it easy to transfer them to tubs or boxes without disturbing the roots.
Allow for Evergreens
The container garden is not complete without some evergreens, especially in regions where the garden can be enjoyed on pleasant late autumn, winter, or early spring days. Well located evergreens are also appreciated from indoors. Balled and burlapped or container-grown, tree and shrub types can be obtained throughout the growing season. For interesting effects, combine evergreens with deciduous trees and shrubs-cherries, crab-apples, deut-zias, and viburnums. With careful clipping, hemlocks, pines, yews, and arborvitae can remain in the same containers for several years. Remember, too, to include some broad-leaved hollies, azaleas, rhododendrons, and camellias.