Aquatics
Read about Aquatics in the Standard Cyclopedia of Horticulture
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Aquatics. A term applied to plants suited to cultivation only in water, particularly to those grown in ponds and tanks. North America is the most highly favored country in the world for the cultivation of aquatic plants. Collections can easily be made to furnish a display of flowers from April to October in the open without artificial heat. There are numerous aquatic plants other than nympheas, nelumbiums and victorias. Some very desirable plants are Acorus japonica variegata (variegated sweet flag), Aponogeton distachyus (Cape pond-weed, or water hawthorn), Caltha palustris and C. palustris fl. pi. (marsh marigolds), Cyperus Papyrus (Egyptian paper plant), limnanthemums in variety. Some of the bog or marsh plants may be used in margins, as many varieties of sagittaria, not omitting the common cat-tail, Typha latifolia, the hibiscus of mammoth proportion, and the beautiful new hybrids with gorgeous flowers of all shades from pink to scarlet and crimson. See Bog-gardening. Figs. 289 and 290 show formal and informal lawn ponds. Soil.—All aquatics require a rich soil, and this without limit, a depth of water from 1 to 3 feet, and ample space to spread their succulent leaves. In a natural pond, in which there is an accumulation of humus overlaying a clayey subsoil, nothing more is wanted, but on a sandy or gravelly bottom it is necessary to place a layer of rich earth 12 to 18 inches deep. In artificial ponds, built of masonry (Fig. 289), a layer of rich soil is necessary if the things are to be planted out, as is best for nelumbiums. The soil best suited for aquatics is a turfy loam, inclining to heavy, and thoroughly rotted cow-manure, two parts of the former to one of the latter, and, when possible, it should be composted some time before using, and turned over two or three times to thoroughly incorporate the manure. When cow- manure cannot be obtained, other thoroughly rotted manure may be used. The next best fertilizer is pulverized sheep-manure, but this, being less bulky and stronger in proportion, should not be used so freely as other manures; one part sheep-manure to nine of soil is sufficient. Chemical manures, ground bone, horn shavings, and the like should not be used unless in extreme cases, and then very cautiously. Tankage may be used to good advantage. It contains dried blood, and ground bone. It is very desirable for permanent beds or soils that may continue two or more seasons without renewing. The bone is not readily dissolved and has a lasting quality. Blood, being soluble, has immediate effect and is a valuable fertilizer, if used sparingly. Depth of water.—In natural ponds, water-lilies are found growing in water from a few inches to 4 and 6 feet deep, but in artificial ponds a depth of 12 to 18 inches will be found sufficient for most nympheas, and 18 to 24 inches is a good depth for victorias. In constructing an artificial pond, a depth of 2 to 2½ feet is ample. Water to the depth of 12 inches above the crowns of the plants is sufficient, and a box containing the soil may be 12 inches deep. Thus a pond 2 feet in depth is deep enough, and will allow a man, with hip boots on, to walk between the plants with ease. For a small pond, less than 12 feet over, a plank laid across will suffice for all operations. Protection.—Where severe frosts are prevalent in winter, and ice 12 to 18 inches in thickness is found, there will be danger of the roots freezing. In such cases, an additional depth of 6 inches will be a great advantage, and a protection of bracken, salt hay, green manure, leaves, or any other non-conducting materials should be used to protect the masonry, in severe weather, against expansion and breakage. To protect tubs, small pools or ponds, cover with boards and pile on dry leaves to the depth of 8 or 12 inches, then salt hay or fresh stable- manure to keep the leaves from blowing away. This is one of the best means of protection against freezing. The general use of concrete work instead of brick and stone is to be commended. Reinforcement makes the walls frost-proof and water-proof. Planting.—All hardy nympheas may be planted any time between the 1st of April and the 1st of September. Those planted early, other things being equal, will give good results the same season, while those planted late will get well established before winter, and will be in excellent condition to start at nature's summons early the following spring. The hardy nympheas differ considerably as to rootstocks. Those of the native species are long and of a spongy, soft texture, and rambling in growth, while the European species have a much larger and very firm rootstock, and grow more compact. In planting, all that is necessary is to press the root- stock firmly into the soil, and if there is any danger of the root rising to the surface, place a brick or any weight upon it, to keep it in position until anchored by its own roots. Tender nympheas should not be planted until the latter end of May or beginning of June, according to location. They should not be planted out before coleus, alternanthera, and other tender bedding plants. They require to be started indoors, and will be grown in pots, which are much handier to plant than roots of the hardy varieties, and can be planted under the water with ease and facility. Nelumbiums should not be planted until about tie 1st of May. Southward the season is earlier. The existing conditions should be such that tubers shall start at once into active growth. They should be already "started" before setting out. The tubers should be laid horizontally in a slightly excavated trench and covered with 2 or 3 inches of soil, using a weight, if necessary, to keep the tubers in position. Plants established in pots or pans are very convenient for planting, and may be purchased when tubers can no longer be procured, and can be planted a month later in the season with good results. The Victoria regia has always been an aristocrat among water-lilies, and few cultivators could indulge in such a horticultural luxury. To grow it satisfactorily, a large surface space with a greater depth of water is necessary than for other aquatics, and a higher temperature is needed at the early stages. It can be cultivated in the open air, but artificial heat must usually be applied and protection afforded, so as to maintain a temperature of 85° F. In 1898 the introducer of V. Trickeri brought the Victoria within easy reach and culture of all lovers of aquatic plants. V. Trickeri is entirely distinct from other known varieties and can be grown in the open alongside of Nymphaea zanzibariensis and N. devoniensis, and under precisely the same conditions. When planted out about the middle of June, the plants grow rapidly, and will develop their gigantic leafage and magnificent flowers in August, and continue to do so until destroyed by frost. V. Trickeri is none other than V. Cruziana, which was never introduced into cultivation until 1898. All that existed outside of its native haunts, on the Parana River, South America, was an herbarium specimen of part, of a leaf. It is now generally and extensively grown throughout the United States and in Europe where aquatics are cultivated. Enemies.—Aquatics, like other plants, have their enemies in the way of insect pests, although in a less degree than most plants. Aphides are sometimes troublesome, or at least very unsightly. These, however, have their enemies, especially the coccinella (lady-bird), insectivorous birds, and so on. When these do not keep them down, a weak application of kerosene emulsion will make a clearance. Another method of getting rid of these pests, especially in a small artificial pond, where an overflow is (or should be) provided, is to take the hose with a spray, using a little force, and drive the insects off the plants, and, as they readily float on the water, the action with the hose will drive them out at the overflow pipe. Recently an insect pest that has its home in Florida has migrated northward, causing some annoyance. The larva of the moth Hydrocampa proprialis eats the leaf, and also cuts out pieces of the same, which it uses for protection, thereby greatly disfiguring the plant, and at the same time making it difficult to get at the enemy. The best remedy for this and the nelumbium moth, which is very much like it, is a lamp trap. Any ordinary lamp placed near the plants at night, and standing in a shallow vessel containing kerosene, will attract the insects, which, on striking the lamp, fall into the kerosene and are no further trouble. For other insects, such as leaf-miners and those which eat the leaves of plants, the best remedy is arsenate of lead. Muskrats are more or less troublesome, especially where nelumbiums are grown. They will eat the tubers in winter and early spring, and will make sad havoc with banks. They will also eat the roots of some nympheas. The best remedy for these is the steel trap. A sporadic disease has also made its appearance. The leaves are affected with spots, which, under a damp, warm atmosphere, spread rapidly. Such climatic conditions, followed by bright sunshine, cause the affected leaves to shrivel up. This greatly weakens and checks the plants. This disease yields readily to a weak solution of bordeaux mixture. The same remedy is also very valuable in ridding the pond of all confervoid growth. Tub culture should be resorted to only from lack of space, or when no other method can be adopted (Fig. 291). For this system of culture, nympheas should be chosen that are moderate growers, yet free-flowering, and other miscellaneous aquatic plants. The tubs should hold from 4 to 12 cubic feet of soil for nympheae, according to the variety, some being moderate growers, others vigorous and robust. The tubs may remain above ground or sunken. If sunken during the warm weather, the roots are kept cooler, and this is desirable, especially if hardy kinds are grown. A great improvement over tubs is a concrete pool 4 or 5 feet in diameter made in the shape of a tub, and 2 feet deep. A circular form 4 or more feet in diameter should be made and the ground then excavated 8 inches larger than the form. This will allow a wall of concrete 4 inches thick. Wire netting should be used for re-enforcing, arranged so as to be in the middle of the wall. Use a mixture of sand, gravel or cinders in the following proportion: two bags of Portland cement, three wheelbarrows of sand, five wheelbarrows of gravel or finely broken stone or cinders and limoide equal to one-fourth of cement. This must be thoroughly mixed before using. After the second day, remove the form and lay the bottom with the same material 4 to 6 inches thick. This will make a strong, durable, water-tight pool and at a very moderate cost. [The standard book on the American culture of aquatics is "The Water Garden," by Wm. Tricker, N. Y., 1897, pp. 120, to which the reader is referred for extensive cultural directions and for lists of aquatic plants. For botanical descriptions of the various kinds of aquatics, with brief, special cultural directions, the reader may consult the articles in this Cyclopedia, under the various genera, as Nelumbium, Nymphaea, and Victoria.]
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