Chapter 10. The Water Garden

By the water garden we mean a garden of plants growing actually in water or in the saturated ground adjacent to water where the soil is periodically submerged. Few features in a garden are more attractive and interesting than the water garden. The pond selected for the water garden can be large or small; it may be constructed by damming off a section of a river, or a tiny stream may be utilized to provide the water supply. It is, however, useless to attempt water gardening unless a continuous supply of water, the year through, is available. A very small amount, even a trickle artificially laid on, will suffice, providing it is continuous. But a water garden which is liable to dry up in the summer is a sure source of disappointment. Where a stream exists, the difficulty of creating a pond is a comparatively small one, granted that by some means, such as a sluice, the flow of water may be regulated; sudden rushes of water in flood times are disastrous to many plants, for example, Nymphceas, Nuphars, etc. In any event, whether the water is derived from a stream or is brought to the pond by means of pipes, a low-lying piece of land should be selected, preferably one where a natural depression already exists. It should be possible to look down on the plants; it should not be necessary to look up at them, as is sometimes the case when the water garden is composed of artificial tanks. The pond assuming that one does not already exist should be made about three feet in depth at the deepest point.

The water garden need not necessarily consist of a pond or lake, it may take the form of a small stream connecting, perhaps, a series of little pools, and eventually emptying itself into a pond or a bog garden at the bottom of the slope down which it runs. The stream may be wide or narrow, deep or shallow. In every case the bottom should be puddled with clay or concreted, and stones, set in the cement, should be placed along its banks to hide its artificial sides and to break the evenness of its outline. In the pockets formed by these rocks may be planted ferns and bog plants. The progress of the stream should be checked at intervals by small dams of stones; these will form a series of shallow pools from which the water may be allowed to trickle in a miniature cascade to the bed of the stream below. The variety of lay-out that this feature permits is, of course, limitless. In constructing a water garden on these lines, the reader will find no surer guide than Nature. Try to place the stones in artistic agreement one with another, so that the final picture may harmonize with its surroundings.

The Water Garden Making The Pond Or Stream

This is today neither so difficult nor so expensive an undertaking as many people imagine. The outlay in proportion to the pleasure derived from the completed garden is indeed small. We should first consider the situation of the artificial water garden, and remember that the aim is to follow Nature as nearly as possible. Let the water garden, therefore, occupy the lowest-lying part of the ground; and to assist in the production of natural effects, the water garden may often be associated advantageously with the wild garden, or the rock garden. Size can be made to suit requirements and the surrounding conditions. A pond only three to four feet in diameter can be made quite enchanting; while a long, narrow vista of water some fifty feet in extent, if space permits, will certainly provide one of the most charming and restful features in any garden. Shape is dependent on space and the other features of the garden. Harmony must ever be the goal of the architect of the water garden, and it should be borne in mind that a series of sharp and erratic curves will never produce a pleasing and natural outline. The design must be simple; curves may be used, of course, but they must be long, sweeping, and natural. On the other hand, not a single curve need be employed; the severely simple square or rectangular pool has a charm all its own. In such cases the garden becomes more formal, the pool may well be bordered by a paved walk, and in the crevices between the stones may grow small wall or rock plants. Where the more irregular and informal shape has been chosen, the grass may be allowed to clothe the gently sloping banks right down to the water's edge, and a knoll of outcropping rock will add beauty to the picture, especially if the water garden is near the rock garden. Marsh plants can be planted in groups from the brink of the pool up to the higher slopes, where bamboos and other shrubs may be used to form a screen and background.

Depth Of Water Required

Few water plants, except very strong growers, which are better excluded even from the moderately large water garden, require a greater depth of water than two and a half feet. To allow for the thickness of the lining of the pond and for the inclusion of soil to nourish the roots, it will be necessary to excavate to a depth of somewhat over three feet. The actual walls of the pond itself are best cut perpendicularly, if concrete is to be used. They must be left sloping if the pond is to be "puddled" with clay, but the earth should be thrown back several feet from the pond, so that the banks on which the marsh plants are to grow may be planted to slope very gently right down to the water's edge. A steep or sharply convex slope down to the water makes the pool difficult of access and is also by no means easy to plant satisfactorily.

[Perry's Hardy Plant Farm A FORMAL LILY POOL

Now as to the impervious lining to keep the water in the pond. There are three that can be used: puddled clay, bricks and mortar, or concrete and cement. We recommend the last of the three as being the easiest to work and the most lasting. Where, however, the subsoil consists of a stiff, sticky, impervious clay, puddling provided it is well done and is carried to a depth of about ten inches is a cheaper and equally successful process. In "puddling," the clay should be cut into small pieces, well watered, and then thoroughly kneaded until it forms a soft, sticky surface.

Digging Out The Pond

It must be remembered that all constructional work will have to be hidden and that a permanently moist margin of soil some two to three feet wide to accommodate marsh plants will be desirable round the pond. It will, therefore, be necessary to excavate to a width sufficient to allow for this; that is to say, supposing it has been decided that the pond shall be ten feet wide, a hole three feet deep all over and sixteen feet wide will have to be dug. This allows for a two-and-a-half-foot margin of moist earth, as well as six inches for the thickness of the wall on each side, if concrete is used. The concrete bottom of the pond need not be more than five inches in thickness.

When the excavation is complete, all loose soil must be dug out and the bottom made thoroughly firm by pounding with a heavy beater. If the soil over which the concrete is to be laid is left loose, it will shrink away and cause the concrete to crack and leak.

Mixing The Concrete

Concrete is a mixture of cement, sand, gravel, broken stones, brick rubbish or similar materials in proportions varying from one part of cement to two of other ingredients for good work to one part of cement to twelve of other ingredients for unimportant work. A useful mixture consists of one part of "Pudlo" to twenty parts of cement, two parts of sand, and four parts of gravel, broken stone, or brick. The cement which binds the gravel or other material together is technically called the matrix, and the material embedded is called the aggregate. Any of the various cements in general use may be used in the manufacture of concrete, but the amateur is recommended in all cases to use good cement, and mix whilst dry one part of "Pudlo" to twenty parts of cement. "Pudlo" may be obtained from most builders' agents. In making concrete, it is important, in the first place, that the aggregate, whatever it may be, shall be deposited on a clean place if on old boards, such as scaffold boards, so much the better so that no dirt shall get mixed up with it. The concrete itself should be made on boards, nailed together on ledges or on three putlogs placed on the ground parallel to one another, forming a rough platform. The aggregate and the cement used as the matrix must then be placed on the boards, the aggregate being measured out first, and the proper portion of cement being also measured out and thrown upon it. Whilst still in the dry state, the materials should be turned over two or three times. The heap is then wetted with water poured over it from a large water-can fitted with a fine rose, and the whole is mixed by again being turned over once or twice, so that the materials may be thoroughly amalgamated. The principal precautions to be taken in the process of mixing are:

1. The water should be added to that portion of the material which the "shoveller" is working upon and not to the mass indiscriminately.
2. The full quantity of water should be added during the third turning, not afterwards.
3. The quantity of water applied must be regulated according to the purpose for which the concrete is intended. For our present purpose the concrete must be in a kind of semi-liquid condition.
4. The "shoveller" must turn the concrete completely over when in the act of casting it from one heap to another.

When using quick-setting Portland cement, no time must be lost between the operations of mixing and depositing the cement where it is required.

When well mixed and in a semi-liquid condition, place about two inches over the bottom and cover with reinforcing fabric, then cover this with a further four to six inches of the aggregate to complete the bottom of the pond and smooth it down firmly; when placing the reinforcing fabric over the bottom leave sufficient protruding so that it may be turned up and overlapped with further fabric around the sides; next build the retaining wall of boards parallel to the earth walls, but six inches nearer the centre of the pond. The gap between the wood and the earth side, when filled up with concrete, will form the two walls A and A'. The supporting boards B and B' are, of course, not removed until the concrete is thoroughly dry. Now construct the two inner walls C and C, each two and a half feet from the outer retaining walls, but ten inches shorter, that is lower, than them. An inflow pipe D and an outlet pipe F should be inserted before the concrete work is completed. As soon as the concrete is quite dry, it should be roughed over, wetted, and then thoroughly worked over with cement-wash, care being taken to see that the corners E and E' are perfectly watertight. If "Pudlo" is added to the cement in the proportion of one part of "Pudlo" to twenty parts of the cement, the latter will be rendered thoroughly waterproof. A waterproof cement-wash called "Glasol" can be bought ready-made, if preferred. This latter preparation is a distinct advance on many previous methods of sealing concrete. A word of warning may here be given it is unwise, quite apart from the shade cast and the dead leaves and twigs that will fall into the water, to construct a pond under or near trees, for their roots run a considerable distance underground, and are in time likely to crack the cement.

Fig. 8. Making the Lily Pond.

A and A' are walls of concrete 6 inches thick; C and C are also of concrete and of the same thickness, but are 10 inches shorter than the outer walls. B to B' shows the overall width of the pond; M and M' are pockets of saturated soil for bog plants; D is the inflow pipe, and F the outflow. The plug G enables the pond to be emptied and cleaned.

The Water Supply

For the great majority of aquatic plants a constant flow of water is not a necessity; the inflow pipe D may, therefore, be dispensed with, and water lost in evaporation may be periodically replaced by means of the hose or by bucket. It should be remembered that, if the border of marsh plants around the pond is to prove successful, the water must never be allowed to fall below the tops of the inner walls C and C, or the marshy condition of the banks within the outer containing walls will not be maintained. Likewise, the water-level must be kept just below the tops of the walls A and A' or too much of the surrounding ground will become boggy. The outflow pipe F is, therefore, a necessity to carry off superfluous water. A plug and outflow G at the bottom of the pond is a useful feature; the water may then be drained away occasionally so that the pond can be cleaned and rearranged as required.

A scheme that will entail more work and a little additional expense is to cut short the inflow pipe D at some little distance from the pond, and to arrange for a series of artificial cascades, rocky ledges, and shallow pool-beds over which the water may trickle on its way to the pond. It is needless to say that careful planting of rock and marsh plants along the margin of this little watercourse can produce some very charming effects.

When the concrete is thoroughly dried, the spaces M and M', between the retaining walls A and C and A' and C, should be filled with a compost of loam and peat, or loam and leaf-mould, which should be banked up so that the tops of the walls A and A' are covered with soil and hidden from sight. The surrounding ground should be made to slope up gently from this point so that turf may, in places, run right down to the water's edge, whence the water and marsh plants may best be surveyed. At other points rocks may be cemented on the tops of the walls A and A' and sometimes just below the water-level. These shelves under the water will form ledges on which aquatics can be planted, and the rocks, which can be built up as miniature cliffs on one side of the pond, will present an excellent contrast to the smooth turf running down to the water's edge.

Planting

In the moist pockets M and M' are planted the bog or marsh plants, those requiring four to six inches of water over their crowns being set under water lower down the bank, while a shade higher up the moist shelf should be grouped those subjects flourishing on cool, moist, swampy banks. The bottom of the pond should be covered with a layer of soil some twelve inches deep, in which the purely aquatic plants may root. The plants which may suitably be grown in and around such a pond naturally vary with its size. If the pond is large, such water-lilies as Nymphcea Marliacea, N. Gladstoniana, and N. colossea may be grown, also Nuphar advena, Stratiotes aloides, and Sagittaria. Intermixed with these may be grouped such vigorous plants as Alisma, Hottonia palustris, Aponogeton distachyum, Cyperus longus, and C. vegetus. The giant Mace Reed (Typha latifolia) should be included wherever space permits. Where the pond is a small one, there are dwarf water-lilies which occupy a comparatively little space, among the most beautiful being Nymphcea odorata minor, N. tetragona, and N. Laydekeri fulgens. These have the further advantage of growing freely and well in as little as a foot of water. Nymphceas cannot feed on water alone, and the soil of their pond or the water around their roots must be enriched, if they are to do really well. This is best done by means of small balls of cow-manure mixed with straw or litter to bind it, made firm, and thrown into the water round the roots of the plants just as the young growth is starting.

The best method of planting water plants in a pond or lake is in pans or flat baskets filled with fibrous loam and a little cow-manure. The pans or baskets are then gently lowered into the water in the desired situation. A layer of enriched mud should cover the bottom of the pond, the baskets resting in this so that the roots of the plants can work out and ramble at will. So well do many plants thrive if provided with conditions of this kind that, where the space is limited, protection must be afforded to the less vigorous species grown, or they will soon become crowded out and choked. Such plants as the Nuphars, pretty as they are, are great offenders in this direction. They spread their strong rhizomes and roots all over the bottom and strangle weaker growers. The Reed Grass, Phragmites, is another of these greedy plants, and its runners should be fished for occasionally with a strong rake and cut off.

The borders of the pond should be hidden with such plants as spread out on the surface of the water, while rooting in the firm soil at the margin. Amongst these are: Myosotis palustris (the Water Forget-me-not), Comarum palustre, Calla palustris, and Veronica Beccabunga. These, prettily grouped, will clothe the actual margin, while beyond them the taller-growing plants, such as Irises, Spiraeas, Marsh Marigolds, with the Sedges, Grasses, and Rushes, thrive on the slightly swampy banks. Many of the Ferns and Primulas love such a situation as this, among them the beautiful Osmunda regalis and Primula japonica. The Bamboos, which are also at home in these conditions, make effective clumps as a background for smaller plants.

Of the ordinary garden plants which prefer a moist soil, many will, if planted in such a swampy border and provided they are well nourished, grow in amazing luxuriance. Spiraa Camtschatica will make a plant from eight to ten feet high, while several of the Lobelias, notably L. fulgens, L. cardinalis, and L. splendens, will often grow from four to five feet in height. Iris Icevigata should certainly be included, and /. orientalis and /. aurea will sometimes make clumps that will reach a height of seven feet. Nearly all aquatics are best planted in spring, but can be planted at almost any time, save, perhaps, in the depth of winter.

Fig. 9. Pools and Waterfalls in the Rock Garden.

The rocks forming the pools in the above diagram must be set in cement to keep the structure firm; the pools are of concrete and lined with cement. A continuous trickle, artificially fed if necessary, will keep the miniature falls running.

Many aquatics that are not really hardy may be introduced for summer decoration in pots sunk either wholly or half-deep in water. These must be removed in winter to warm water tanks under cover of glass. Every year something new in aquatics is being introduced, for there seems to be no limit to the multitude of aquatics native to the tropics, and very many of them are supremely beautiful.

Care Of The Water Garden

Once planted, many of the aquatic and marsh plants are better if left undisturbed and are only lifted and replanted when they appear to be unhealthy and ailing. Others, however, are much like hardy herbaceous perennials in their requirements and do best if they are lifted, divided, and replaced every third or fourth spring. Some of the water-lilies make tremendous leaf-growth and consequently little bloom, for the leaves cover the surface of the water and prevent the sun's rays from playing on it. This warming of the water by the sun's rays is essential to most aquatics, especially the Nymphceas, or water-lilies. The strong leaf-growth must, therefore, be periodically cut away in the spring, and, if necessary, the roots should be divided. This thinning-out will produce more bloom on the plant and will restore adequate breathing-space to its neighbours.

Many people are troubled with an objectionable slimy green growth called Blanket Weed. This covers the surface of the water in hot, dry weather, usually in spring and summer. It may be disposed of by adding one ounce of copper sulphate or half an ounce of potassium permanganate to every fifteen thousand gallons of water in the pond. A second application should be made a week later, should the first have proved unsuccessful. These solutions will harm neither plants nor fish.

Propagation Of Aquatic Plants

Some aquatic plants, as they are termed, are propagated by seed, but they are mostly increased by division of the roots. The seeds, when sown, must be placed under water. In other respects aquatics require the same general treatment as other herbaceous plants.

The Culture Of Water-Lilies

Most of the Nymphcea grow best in from one and a half to three feet of water; the stronger growers flourish in a depth of from three to four feet. No lilies should be planted in water of less depth than a foot or eighteen inches; in water shallower than this they are easily damaged by frost. The rhizomes, or roots, should be packed in a compost of fibrous loam, leaf-mould, and cow-dung, and must be placed in an openwork basket, out of which the roots may ramble over the bed of the pond and seek nourishment. Where a layer of deep rich mud stretches over the pond bottom, the plants will grow luxuriantly and there will be little need of an additional stimulating compost. The roots should be securely tied into the basket, which should be weighted so as to act as an anchor when the plant is lowered into the water. Any time between April and June is suitable for planting these lilies, and at this time, too, the roots may be divided; this is usually advisable every three to four years. Don't plant the clumps too close together; study the colour-scheme while planting, and remember that it is useless to try to grow water-lilies under overhanging trees.

Plants with small or weak rhizomes are best planted in a tub for the first year or so, afterwards they may be transferred to the pond. Where tubs are used, a little water must occasionally be added to make up for evaporation. The lilies must not be permitted to become overcrowded; should this happen, they must be thinned out in spring, preferably in May. The rhizomes must be cut through between the growth-producing stems, and the roots should be dragged up from the bottom of the pond. There are many of the more vigorous-growing kinds, such as N. Marliacea, that will require this treatment every two to three years; that is, twice as often as is necessary in the case of their less luxuriant fellows, some of which hate being disturbed and will thrive for many years in one spot. N. odorata and iV. Laydekeri are examples of these.

When plants make profuse leaf-growth, the foliage is thrust up out of the water and stifles the blooms other leaves spread out over the water and prevent the sun's rays from reaching and warming it. Water-lilies will only thrive in sun-warmed water, therefore a severe thinning of these inordinate leaf-growths must be periodically made. This thrusting of the leaves above the water surface is also a sign that the plant requires deeper water or needs to have its crowns thinned out.

Water-Lilies In Tubs

Lilies are often grown in tubs, for space will often not permit of their being grown in any other manner. Tubs are not, however, recommended where other means are available. The tub should be painted or tarred outside, but not inside. It should have a vent and plug in the bottom for drainage, and must be sunk with the brim just below ground-level. A surround of crazy paving will help to hide the rim of the tub, and the sun's heat that it will reflect will warm the water and stimulate the growth of the plant grown in it. The more vigorous-growing kinds of Nymphcea, unless thinned vigorously every two years, should not be grown in tubs, but there are many small species, as for instance N. odorata minor and N. tetragona.

Plant the lilies one in each tub, in weighted baskets, as in pond planting, but the compost must not be too rich (equal parts loam and leaf-mould will suffice) or the leaf-growth will be too luxuriant. Six inches of soil should cover the bottom of the tub. It is quite unnecessary to change the water, but evaporation must be compensated for. The surface should be cleared of Blanket Weed and slime, and a sharp look-out must be kept for water snails and other pests that frequent the plants, especially when they are grown in tubs.

Plants For The Water Garden

NOTE. For Fuller Cultural Details, see Chapter 12, Alphabetical

List of Plants for the Rock, Wall, Paved, and Water Gardens.

NOTE. Although Nymphaeas can be raised from seed as stated, the usual method of increase is by division of tubers, as named varieties are not likely to come true from seeds.

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