SHRUBS UNDER TREES
It is often a vexed question what to plant under trees when the space is bare, and sometimes there is an ugly view seen beneath the branches to shut out. Evergreens are the sheet anchor, relieved with a few deciduous shrubs grouped amongst them.
Much depends upon the tree, whether a Beech or an Oak, a Maple or a Chestnut, and so on, as trees vary considerably in their method of rooting, as well as in the shade they give during the summer months. This affects the welfare of the plants underneath. Such trees as Oak, Ash, Plane, Birch, and Horse Chestnut are inclined to root deeply when they have grown to a fair size, and do not interfere directly with anything underneath them, although the roots extract much moisture from the soil.
On the other hand, Beech, Elm, Lime, and Sycamore are more surface-rooting, and their roots often get entangled with and gradually kill plants growing near them. Beech and Elm are the greatest offenders, and grass frequently perishes under these trees. A few liberal soakings of water in dry weather are beneficial to shrubs or anything else under trees, but the soakings must be thorough, as mere sprinkles are more harmful than otherwise. The spread of large tree branches should also be noticed in summer, as sometimes one or two of the lower ones may be removed with benefit to the shrubs, judicious cutting away letting in light and air.
The best of the larger growing evergreens to use under trees are Laurels, both common and Portugal, Yews, Box, Osmanthus, Aucubas, Phillyræas, common and oval-leaved Privet, Ligustrum sinense, and Rhododendron ponticum. Of these Yews, Box, and Osmanthus are perhaps as successful as any. The Osmanthus is not usually considered suitable for this purpose, but it succeeds well in the shade, and keeps a good dark-green colour. Hollies are sometimes recommended, but, though they may occasionally thrive under trees, it is not advisable to use many of them, as they are more often a failure, becoming thin and straggling in the course of a year or two. Of dwarf-growing evergreens Berberis Aquifolium, Butcher's Broom (Ruscus aculeatus and R. Hypoglossum), Cotoneaster microphylla, Euonymus japonicus, and E. radicans, with their respective varieties, Skimmias, Gaultheria Shallon, Ivies, especially the common English, Irish Ivy, and Emerald green, Pernettya mucronata, St. John's Wort (Hypericum calycinum), and Vincas can all be recommended, as they all do well in the shade, and most of them will flower freely.
For a very dry spot where nothing else will grow the Butcher's Broom and St. John's Wort should be planted, as both will grow and thrive where other plants die. With deciduous shrubs under trees the difficulty is not so much in getting them to live as in coaxing them to flower, but a few of them will do well in the shade, and, as a rule, bloom freely. Of these the best are the common and White Brooms, Azalea pontica, Genista virgata, Philadelphus, Forsythias, and Daphne Mezereum. The shrubby Spiræas may also be used sparingly in a fairly light and open place, though plenty of sun is required as a rule to enable them to flower properly. In addition, though their flowers are insignificant, Cornus alba with its red stems in winter, the Snowberry (Symphoricarpus racemosus), which is laden every year with white berries long after the leaves have fallen.
The question about shrubs growing under trees is so frequently asked that the names of those most successful are given, but generally the beauty of the tree is lost when smothered up with evergreens and other shrubs beneath its spreading branches. A tree is a picture in itself, and it is pleasant to see the grass creep to the branch edge and then cease, leaving a brown earth patch under the canopy of foliage.
Shepherdi Holly, Tree Ivies, and Berberis stenophylla, it may be mentioned, are a success under trees.