This section is from the book "How To Make A Flower Garden", by Wilhelm Miller. Also available from Amazon: The Well-Tended Perennial Garden: Planting and Pruning Techniques.
N0 BOOK on floriculture can be complete without a chapter on trees. Some of the showiest flowers are borne on small trees which are suitable for gardens of moderate size. The foliage of trees and shrubs is indispensable as a background for flower borders. Trees make the sky-line - an important feature. They are often invaluable as windbreaks, and they supply shade and retain moisture - conditions which are essential to the life of some of our choicest flowers.
Who has not seen trees so profusely covered with bloom as to almost hide the branches and young leaves? Witness the plums and cherries, including those that come to us from Japan; thorn-apples, comprising the English hawthorne and the great number of American species, all varieties of crab-apples, and ornamental peaches. With them naturally go Japanese quinces, roses, and spireas. Many of the trees mentioned are ornamental in fruit as well as in flower. The Juneberry forms a connecting link between snowstorms and summer. Its pure white flowers often appear in contrast with those of the redbud. The flowering dogwood is another tree noted for its bloom. Some of the willows would be especially appropriate near a bog garden, their catkins and brightening bark frequently making the first announcement of spring, an announcement which is quick to be repeated in a different manner by the song-sparrow perched on one of its branches. Trees of a larger size noteworthy for their flowers are the red maples, the horse chestnut, the catalpa, the linden, and the locust. The sugar maple and Norway maple are also worthy of mention, on account of their yellow flowers, although these are not quite so rich in colour as those of the maple first mentioned.
The flowers of some of the trees named are quite fragrant when in bloom. This is especially true of the common locusts and lindens. The tulip tree, with its large, glossy leaves of unique shape, is in full summer attire when the blossoms appear, and the latter are frequently unnoticed, although they are quite deserving of admiration. With the tulip tree should be mentioned the magnolias, although it must be remembered that there are many places in the United States where these do not thrive.
But trees noted for their blossoms are not the only ones that are suitable for planting about a flower garden. The flower garden that I have in mind is not one devoted exclusively to the raising of flowers which are to be cut for home decoration, and which should be planted in rows and beds for ease in cultivation, but is a garden arranged primarily to show a beautiful composition in which flowers appear to their best advantage, because they have a background of shrubs and trees. A single tulip appearing against the deep shade of a shrub or low-growing tree may be more beautiful than a bed, without any setting, that contains hundreds of plants. The same is true of a group of trilliums growing under a low-branching linden, or a showy lady's-slipper in the shade of a white pine. I have in mind a low-branched soft maple where the ground underneath is carpeted with wild violets; an elm about whose buttressed trunk is a thick growth of white adder-tongues, and a beech shading a beautiful group of ferns. One can imagine a beautiful fall picture where a pepperidge tree, which has quite inconspicuous flowers, but has an autumn foliage more brilliant than that of our other native trees, serves as a background for sunflowers, golden-rods, and asters.
Such would indeed be a beautiful picture.
Late to appear are the tulips of the liriodendron.
The brilliant colouring which the foliage of certain trees takes on in autumn is usually more satisfactory than that of such trees as the purple-leaved plum and the purple-leaved beech, which retain their peculiar colouring during the entire season. Care should be taken not to use too many trees whose foliage is abnormal either in colour or shape. The leaves of our common trees present a wonderfully varied assortment of green, the most restful and satisfactory of all colours. No colour makes a better foil for a flower, whether it is seen out-of-doors or as a bit of table decoration. One can seldom make a mistake, therefore, in selecting native American trees for planting about a flower garden. The list of these might be enlarged by adding Norway and sycamore maples, the European bird cherry, and any other foreign trees which harmonise with our own. The European cut-leaved birch is a beautiful tree, but it seems to me that its place is on a lawn just in front of a group of pines. When planted with flowers, it would seem to be competing with them for admiration, instead of helping them by making an effective contrast. If the purple-leaved tree is used, my preference would be to place it in the background, with some low, green foliage between it and the herbaceous plants.
I confess that I have not much love for the golden-leaved varieties of trees, as they always remind me of sickly specimens. As for deciduous trees, they should be planted just after the leaves drop in the fall, or soon after the frost comes out of the ground in the spring. They may be obtained of small size from reliable nurserymen, or sometimes of larger size from the neighbourhood of the place to be planted. The hole in which the tree is to be placed should be considerably larger than the space occupied by its roots, unless the whole space has been recently filled or deeply plowed or trenched. Usually a tree, especially a tree of large size, should be planted a little higher than it stood before moving, as the ground will settle, and a tree looks better springing from a slight mound than it does rising from a hollow. The mound might indeed be extended into a ridge, receding where there are bays, but coming forward and helping give emphasis to the points, so that the flower garden would occupy a gentle valley. At the time of planting, the ends of the roots should be cut smooth and the space between them carefully filled in with good friable soil, and this should be thoroughly compacted by pounding.