There are subjects, such as the Willow, which become particularly associated with the waterside, because their love of moist places causes them to grow luxuriantly there. The Willow itself is not only well suited by such conditions, but possesses forms which droop gracefully over the water. There are, however, many other shrubs and trees besides this.
The water in a garden may be pool, lake or streamlet. There are cases where it is impracticable to drain a garden except by collecting the water in some low-lying part. If this is done, a pool, large or small, according to the size of the place and the rainfall, is formed.
Should a garden be drained? It depends upon the soil and situation. A garden-maker who has to operate on heavy, retentive soil, on a low-lying site, will find it much to his advantage to drain. Without drainage, it may happen that the surface soil is waterlogged for many weeks during winter, and this is as bad for most shrubs and trees as it is for most other kinds of plants. Such a soil, in such a situation, would certainly be improved by laying drain pipes or "tiles" in trenches about a yard deep, and five yards apart.
It is not uncommon to drain land, but it is less common to retain the water which the drains collect. The general idea is to get rid of it by the simplest plan available, such as to turn it into the nearest ditch. But the garden-lover should think twice before deciding to get rid of the water. He should think during a dry spell in summer, as well as during a wet period in winter. If, in the latter, he is inclined to get the water off the place as quickly as possible, in the former he is likely to think only of how he can keep it.
When drain-pipes are laid, it is easy to arrange for them to converge on a low spot, and discharge their water into a prepared pool instead of into a ditch. The bottom may be puddled with clay or lined with concrete in cases where there is a doubt about sufficient water gathering to hold through the summer; but where it is reasonably certain, from the retentive nature of the subsoil, the size of the place, and the rainfall, that a good body of water will remain, no special provision need be made.
The one serious drawback to a pool which is fed merely by surface water, is that it tends to become stagnant and foul. There is not the constant change of water which occurs when a stream runs into and out of the pool. The true garden-lover will never permit such a pool to become a nuisance and an eyesore. He will plant it with water-lilies, and clean it out every few years, so that it is a feature of interest and beauty.
Another way of getting a pool or small lake in a garden, is to take advantage of the passage of a stream. At a selected point or points the bed may be widened.
It may be possible, in some cases, to split a stream into two, taking the sections round an island mound.
There are, of course, instances where an area of swampy ground exists, which cannot conveniently and economically be drained. But the garden-lover is not helpless. He has it in his power to make what might be a "dismal swamp" or "slough of despond" an interesting feature of the garden by judicious treatment with proper plants.
We see, therefore, that "waterside" has a rather wide meaning for the gardener. It may be still or it may be running water. It may be a self-contained pool or it may be a lake with inlet and outlet. In any and every case, we can find means of dealing with it. Whatever it may be, we can seize upon it and convert it into a source of beauty and interest from the gardening point of view.
To deal with all the plants suitable for the waterside would be outside the scope of this work. Many of the best are Alpines or hardy herbaceous plants, and these have been dealt with in the sister volumes: "Alpine Flowers and Rock Gardens," and "Hardy Perennials and Herbaceous Borders." But there are many beautiful shrubs and trees which will supplement the good effect of the other classes, and these we may appropriately consider.
Of the larger trees one of the best is the White Poplar, or Abele, Populus alba, which attains to its finest proportions on a moist site. But practically all the Poplars will thrive in moist soil. The Aspen, Populus tremula, becomes a magnificent tree in a moist clay soil; and its flickering leaves are never still.
Fig. Trees and shrubs by the waterside. Water Garden at Aldenham House showing successful planting of trees and shrubs. See Chapter 22. Photo by R. A. Malby.
The various Alders (Alnus) will also thrive, indeed, they naturally inhabit moist places. The yellow-leaved form is bright.
The Ash, the water and swamp Oaks (Quercus aquatica and Q. palustris) and the Elder will succeed. Elders are fond of damp spots, and on such sites one may sometimes see thickets spring in a few years from bird-sown seeds if there is shelter.
Many of the Conifers will thrive, notably Abies Menziesii, the Cypresses, Austrian Pines, Tsuga canadensis, Thuja gigantea and Taxodium distichum. The last, the Deciduous Cypress, browns over in autumn.
As regards the Willows, there are two forms of the variety of White Willow (Salix alba) called vitellina, which are worth planting for their coloured stems, one yellow, the other red; they are sometimes called respectively the Golden Willow and the Cardinal Willow. There are several Weeping Willows. Perhaps the best known is Salix Babylonica,but the Kilmarnock Weeping Willow, which is a form of the Common Sallow, Salix caprea, called pendula, is very popular. There is a yellow-stemmed form of Babylonica called ramulis aureis. The Willows with coloured stems should be particularly considered, because they are so bright and cheerful in winter when the leaves are down. A line of Willows may often be planted with great effect to overhang a section of a stream. It may also be remembered that they may be planted in swampy spots. Here the Sallow comes in very useful. Its catkins are conspicuous in early spring.
With respect to flowering shrubs, few are likely to do better than the Viburnums, including the Guelder Rose, V. opulus sterile, and plicatum, the Dogwoods, Halesia tetraptera (the Snowdrop Tree), the Sweet Gale, Kalmia glauca, Berberis Darwinii, such Brambles as Rubus biflorus (with white stems), R. laciniatus and R. fruticosus, the Cotoneasters, Ledum palustre, the Tamarisk, the red-berried Elder (Sambucus racemosa) and its forms such as laciniata and plumosa aurea, Spiraea Douglasi with red and S.Lindleyanawith cream flowers (and of course the herbaceous meadow-sweets) and the fine Reed (Arundo donax) which is second only to Gynerium argenteum in beauty of white plume.
An idea for using the Bamboos is to set them in a series of isolated clumps alongside the approach to the water. For this purpose such imposing herbaceous plants as Rheum palmatum and Gunnera manicata will also be useful; they produce gigantic leaves.
Elaeagnus macrophylla is a handsome shrub for the margin of water.