It may even be necessary to keep the plant itself over the winter. This course is followed in case of seedling water-lilies which, during the year, have not advanced sufficiently to produce either seed or tuber. Though tubers have been formed, they may be immature and likely to decay before the next spring and it then becomes necessary to resort to other methods to retain the variety.

The experienced grower readily foresees which particular plant is liable to be in this undesirable condition in the fall and lays his plans accordingly. As soon as he has decided that the plant is worth keeping something which usually can be foretold in late summer – he digs it up and repots in a shallow box, five to six inches deep and about two feet square or even larger. After boxing, the plant is returned to the pond, where it will continue to grow until fall, at which time it can be transported bodily to a tank in the greenhouse. By keeping the water in the tank at ordinary greenhouse temperature, that is to say, 60° to 65° F., growth will not be interrupted, though somewhat retarded, and the tubers have an opportunity to mature. Following this method, it is highly probable that in the spring we will not only have the parent plant but likewise a number of small tubers, which will bloom the same season.

The temperature of the water in these growing tanks should be about the same as that of the house in which they are placed, that is to say, about 65° F. A little more heat is desirable for Nymphaea Sturtevantii, and a greenhouse pipe may be passed through the tank to supply the requirement. In an emergency, heating the tank with a coal-oil stove placed under it may be resorted to, but cannot be recommended as a general rule.

Keep the water level so that the edges of the pots are about two inches below the surface. When the leaves appear, keep them just floating, using blocks underneath to regulate the heights of the pots.

Many hybrids are practically sterile, and must be propagated from the” roots.” The same method may also be used for the true species. Indeed, one can never depend on the purity of seed where several kinds have been grown in the same tank. Natural hybrids are common. For pure stock of tender water-lilies we must commonly have recourse to the following method, beginning a year in advance.

A young plant of the desired kind is kept all summer in a 6-inch pot, in very shallow water. It will make good growth for some time, and then all the leaves will die off. If this does not occur naturally, it must be induced in August or early September, by raising the plant to the surface of the water, or partly out.

When the leaves are gone, a tuber the size of a robin’s egg should be found in the pot. Now remove the pot from the water, and let it become nearly dry. Take out the tuber, place it in clean sand, and keep it in a moist, temperate, or warm greenhouse atmosphere until next March. Never let the tuber get hard and desiccated, nor should it get really wet. It needs only a gentle air-drying.

Now, to propagate, set pot and sand and tuber in a warm tank in March. The tuber should be planted about an inch deep. Soon a shoot comes out, sends up leaves to the surface of the water, and makes roots. When one good floating leaf is established, wash away the sand from roots and tuber, carefully break off the shoot with its roots from the apex of the tuber, and replant both plantlet and tuber. Of course the plantlet now goes into rich earth. The tuber should give off at least one more shoot. The first
plant is pushed forward for-flowering, the next is kept to form a tuber for the following year.

The easiest tender nymphaeas to grow, to keep over winter, and to increase from the tuber, are N. flavo-virens, N. Wm. Stone, and N. Mrs. C. W. Ward. The easiest to grow from seeds are the blue lotus, Zanzibar water-lily, and Nymphaea flavo-virens.

The new season’s work begins about March 1st, when the tubers must be taken from the sand storage and potted up, according to size, in a 3- or 5-inch pot. Use a plain, heavy loam without adding either sand, leaf-soil or manure, but a little sand may be placed on the surface of the soil after potting is done. This will help to keep the plant free from algal growth, and to a certain extent prevent the accumulation of scum on top of the water.

The pots containing the tubers must be kept in water. For this purpose galvanized iron tanks painted with red lead are best. Tanks of wood may serve, but have a tendency to leak. Besides, they are awkward to handle. Copper tanks do not give good results. A tank six feet long and four feet broad, with a height of about nine inches will be found most ;,;erviceable. These can be obtained at a cost of from six to eight dollars. The tanks must be flushed every day or two, to remove any matter which might float on the surface and prove injurious to the young plants.

As soon as a plant gets too big for its pot, shift it into a size larger and continue to do this up to 7-inch pots. Never let a plant suffer from need of shifting. Giving a plant room and the best opportunities in early life, will largely counteract the effects of adverse conditions when it is older. This is a fundamental rule in water-lily growing which never should be lost sight of by the grower. It is all-important.

For various reasons it may be impossible to obtain seed of some plants. Many of the hardy nymphaeas produce it but rarely.

The hardy water-lilies give no trouble in winter as they are simply left outdoors where they grew. They take care of themselves! Natural ponds must obviously remain undisturbed; artificial ponds can have some water drained off, and in places where the winter cold is likely to be very intense, the plants can be covered with planks, hay, leaves or any other protective material ready at hand. Where hardy nymphaeas have been grown in tubs plunged in the ground, a simple covering with hay is sufficient. Loose tubs can either be plunged in the ground or removed to a cool cellar. When spring returns, the covering is removed at the same time as it is taken off other garden plants; the tubs can be brought from the cellar in March.

On the other hand, wintering the tender, day blooming water-lilies is really a difficult matter, requiring some skill and a good deal of space. Full-grown plants may be taken up bodily before frost, either in their tubs, or with a big ball of earth, and wintered in a large, warm tank indoors-there they will keep on blooming, with plenty of heat and light; or will merely keep alive in lower temperatures. Plants which have grown large and flowered, will not live over in any other way, excepting Nymphaea flavo-virens and its kin. Usually, therefore, the old plants are left outside to die; but the tubers may be collected.

The night bloomers are wintered more easily than the tender day bloomers. The plants may be taken from the pond either in their tubs, or with a large ball of earth, in October, and allowed to dry off slowly. In a month’s time there should remain from each plant one or two small tubers. Sometimes the tuber is smooth and oval; sometimes it is of a very irregular shape. It is kept in dry sand as prescribed for the day blooming kinds. In February or March the tuber is planted in sand and sunk in a warm tank. Soon it sends out a host of shoots. These mature one by one. They may be broken off and potted separately as soon as they have one or two floating leaves. Each tuber, therefore, of the night blooming waterlilies will produce enough plants to stock a large pond. It is a wise precaution to keep one or two plants in small pots all summer, just to form tubers. The old plants sometimes rot completely when taken in.

Tender nymphaeas that are to be carried over the winter for another season must be taken up before there is a chance of a killing frost, that is between October 15th and 30th. If possible, drain the pond of enough water to facilitate the work, removing the leaves from the plants and cutting off the roots about a foot from the center. Then take up the plants with as much soil as will cling to them.

The best winter quarters for the tender nymphaeas is under the bench of a greenhouse with a temperature of from 60° to 65° F.

With the mud clinging to them they show no differences. But most of the stellata type, such as Nymphtaea cterulea, have a central crown only, while others have one large and a varying number of smaller tubers. These mature during the next month or so, finally going into a dormant condition. Many of the stellata type produce tubers very sparingly and it is often necessary to retain the old rhizome. This old rhizome, however, has a tendency to rot during the winter when placed under the greenhouse bench, to prevent which it must be kept in a growing condition. This is best accomplished by potting it into a 7-inch pot, which is then submerged in a tank in the greenhouse, only a slight covering of water being essential. By the next spring the plant will be found ready to make a vigorous growth.

IN JANUARY

About the middle of January look over the collection to see what can be saved and what must be thrown away. In this the greatest care must be exercised as many of the most valuable types produce tubers often not larger than a pea.
While sorting the tubers, carefully remove the mud clinging to them, taking care not to injure the eyes. Then place them in rather dry sand, where they can remain till the time comes to start them into growth.