Nymphaea

Plant Characteristics
Habit		aquatic
Lifespan:	⌛	perennial

Cultivation

Exposure:	☼	sun
Water:	◍	wet
Features:	✓	flowers, foliage
USDA Zones:		1 to 11
Sunset Zones:		all zones
Flower features:	❀	red, orange, yellow, blue, purple, pink, white, double

Scientific Names
Nymphaeaceae >	Nymphaea >

Read about Nymphaea in the Standard Cyclopedia of Horticulture
Nymphaea (from Nympha, in Greek and Roman mythology, a nature-goddess). Syn., Castalia. Nym- phaeaceae. Water-lily. Pond-lily. Nymphea. The most showy of aquatics (except Victoria), inhabiting the North and South Temperate and Tropical zones. Herbs, perennial by horizontal or erect rootstocks or tubers, rooting in mud. covered by 3 in. to 6 ft. of water (rarely in bogs not submerged): Lvs. floating, or when crowded rising a few inches above the water, round or oval, entire or dentate or sinuate, fissi-cordate, often sub-peltate, 2 in. to 2 ft. across: fls. mostly showy, white, yellow, blue, and red, in all shades, 1-12 or 14 in. across; sepals 4; petals and. carpels many; stamens numerous; pistil with a broad cup-like depression in the center of the fl., surrounded by a ring of fleshy processes, the carpellary styles, and with a knob at the center.—About 40 well-marked species, with numerous local varieties and many cult, hybrids. The petals and stamens of Nymphaea appear to be attached to the sides of the ovary; but this surface is to be considered as the outside of a cup-like receptacle, its cavity being completely filled by the radially placed carpels, with whose backs it is fused. Several species show easy gradations from sepal to petal and from petal to stamen, thus illustrating the homology of floral parts. The peduncles and petioles are traversed by a number of longitudinal air-canals, from whose walls star-shaped cells and rounded cell groups project inward; in the walls of these stellate internal hairs, are imbedded numberless minute crystals of calcium oxalate; they are objects of great beauty in microscopical sections. The distribution of these, as also of the air- canals, differs in different species. (Figs. 2541 to 2544.) Three types of leaf may be distinguished: (1) Very thin and fragile submerged leaves on short petioles; (2) floating leaves, thicker in texture, with stomata and palisade cells on the upper surface only; (3) aerial leaves, leathery in texture, sometimes, at least, bearing stomata on the under surface. The leaves spring from the rhizomes in spiral orders of varying complexity, from two-fifths up. The growing apex of the stem is protected by the colorless stipules and a dense growth of long fine hairs. A group of roots comes off from the' stem just below each leaf. The flowers are extra-axillary, arising as members of the leaf spirals or in a spiral of their own. The rhizomes of species which dry off in the resting season (Lotos, Hydrocallis; Apocarpiae) become protected by a strong corky bark; others remain continually in a state of more or less active growth. Habits of opening.—The flowers of every species open and close at a particular time each day, so that in a pond with eighteen or twenty kinds there is some change taking place at almost all hours. The hours of blooming are fairly regular, though the tropical species are more sluggish in cool weather, and the hardy ones are irregular in very hot times. Each flower opens from one or two to five or seven successive days (or nights), being about an hour later to open and an hour earlier to close on its first than on subsequent days. The flower then goes down into the water by a spiral coiling of the peduncle (or simply bending over if in shallow water), where the seed ripens. When in six to ten weeks the pod matures and bursts, the seeds rise to the water-surface and float for several hours by means of a buoyant aril. This finally decays and drops the seed at some distance from the parent. To secure these, the floating seeds may be dipped up in a wire sieve, or better, the pods may be inclosed in muslin or cheesecloth bags before ripening, all of the seeds being thus secured. The hybrids.—The species of a single group hybridize very readily among themselves, and in the Lotos and Eucastalia groups the hybrids are more or less fertile. By means of this condition all shades of color have been obtained, from the pure white N. Lotus var. dentata to the dark crimson-red N. rubra. In this group and in Castalia varieties have so multiplied of late and fanciful names have been so freely given that an accurate classification of all of them is no longer possible. In the Brachyceras group, hybrids occur almost certainly if N. zanzibariensis is grown in the same pond with others of the group; thus have originated some very fine varieties. Outside of single groups, no genuine hybrids have yet been produced. Between the apocarpous and syncarpous species, a hybrid would be impossible. Authorities differ as to the best time to transfer pollen. Certain it is that the flowers are pistillate on the first day of opening, the pollen being shed on succeeding days or late on the first day. Some say that pollination should take place in the early morning hours, about daybreak; others consider the time most favorable just as the flower is closing for its first time. Trouble with the names.—The water-lilies and yellow pond-lilies or spatterdocks were together included by I inu.ru under the genus name Nymphaea. In 1805 Salisbury first separated these two parts of the genus. The water-lilies he called Castalia and the spatterdocks Nymphaea. J. E. Smith, writing two years later, disregarded Salisbury's work and called the two groups Nymphaea and Nuphar respestively. Thus Castalia, Salisb. - Nymphaea, Smith, and Nymphaea, Salisb.- Nuphar, Smith. Salisbury, contrary to good usage and the present International Rules (article 45), coined a new name for the group containing the larger number of species, and arbitrarily changed nearly all of the specific names. His names, however, never came into general use, but Smith's were generally adopted. Strict adherents of the "law of priority" have recently revived the generic names of Salisbury. The principle of fifty years of accepted usage may well be extended to this case, making it unnecessary, as it is also unfortunate, to revive the old name Castalia for these well- known and popular plants, which are habitually monographed under Nymphaea. The name Castalia is not adopted by most European botanists. Briquet, of the international committee on nomenclature and under whose name the international rules are issued, writes the author that the rules definitely mean to authorize Nymphaea rather than Castalia. Until the first edition of this Cyclopedia, several specific names were confused, but this difficulty is mostly corrected now. In reading of aquatics prior to 1900, it is well to remember that many British botanists include all blue water-lilies of the eastern hemisphere (or all except the Australian forms) under the name Nymphaea stellala. N. caerulea of B. M. 552 and N. scutifolia, DC., are really N. capensis. The true N. caerulea was long known in American gardens as N. scutifolia (Tricker, "Water Garden," 1897). N. ampla of gardens may be either N. amazonum or N. Lotus var. dentata (see "Waterlilies: A Monograph of the Genus Nymphaea;" by H. S. Conard. Carnegie Inst. Publication No. 4). The true Egyptian lotus.—Among common names the term "lotus" has been remarkably misapplied. It seems to be consistently used among us for the genus Nelumbo, Nelumbo nucifera being generally styled "Egyptian" or "sacred lotus." Historically this is entirely wrong. Nelumbo is not native in Egypt, and is not now found there in a wild state. It was cultivated extensively along the Nile in the Roman period, probably for food, and the flower is supposed to have furnished the design for one form of capital of the Egyptian columns. It is a native of southeastern Asia; is found near temples and carved on the walls of cave-temples in Hindustan, showing a veneration, which it shares, however, with Nymphaea stellata, N. rubra and N. Lotus. Nelumbo seems to have been regarded as sacred about temples in Japan and China. In Egypt, however. Nymphaea caerulea and N. Lotus, the "blue lotus" and "white lotus," are indigenous. The root (rhizome) of the former is said to have been pointed out as edible by Isis—or by Menes; its flowers, buds and leaves are often depicted on the monuments, the first sometimes in color. The flowers are figured among offerings under the fourth dynasty (3998-3721 B.C.), and the plant is certainly known from the fifth dynasty. Petals of this and of N. Lotus were found in the tomb of Rameses II, the Pharoah of the Israelitish captivity. N. Lotus was less regarded than N. caerulea in Egypt, though an object of veneration in India. Herodotus and other ancient writers speak of these water-lilies indiscriminately as the "lotos" of the Egyptians. With these facts, and the additional one that, except as referred to above, Nelumbo never appears in Egyptian carvings, the identity of the sacred lotus cannot be doubted. But the erroneous use of the word lotus is deeply rooted and may never be supplanted, and it is necessary to remember that the so-called "Egyptian lotus" is not the plant of the tombs and monuments. (The lotus of Tennyson's poem, "Lotus Eaters," is still another plant, a shrub or tree, which hangs out over the water; and the genus Lotus (which see] is distinct from all of these.) The Marliac hybrids.—Two types of hardy free- flowering hybrids akin to -V. alba and its variety rubra, but of uncertain parentage, have been introduced sinc<- 1888, one of sturdy habit, raising its leaves (4 to 8 inches across) and flowers (3 to 6 inches across) well out of the water when crowded, the other slender in growth, the leaves (3 to 6 inches across) and flowers (2½ to 4 inches across) usually floating. From 1888 to 1900 all of these superb varieties were introduced by M. Latour-Marliac of Temple-sur-Lot, France, whose methods, however, remain a mystery. Excellent culture combined with careful selection and wise hybridization have brought about these magnificent results. The first or Marliacea group seems to involve N. alba as one parent. The second started with a hybrid of N. alba var. rubra and N. tetragona known as N. Laydekeri var. rosea, to which is added in varying degrees blood of N. alba var. rosea and N. mexicana. But this does not adequately account for the whole group. Nearly all kinds of both groups are entirely sterile. Important species.—The following account, which contains 200 varieties and about 48 synonyms, may seem rather formidable to the beginner, but the species of first importance are only eight in number: N. Lotus, N. rubra, N. tuberosa, N. odorata, N. alba, N. mexicana, N. flavo-virens and N. zanzibariensis. The greater number of the other names represent garden varieties and hybrids. It is impossible for any form of arrangement to be clear and logical on the one hand, and exhibit natural relationship on the other, at least, in a genus so greatly modified in cultivation. However, the true species may be distinguished in the treatment, the derivatives being apparent by description or hybridization sign (x) or otherwise. The best water-lilies for amateurs.—Tender day-blooming kinds: N. Pennsylvania, light blue; N. zanzibariensis, deep blue; N. flavo-virens, white; Mrs. C. W. Ward, pink; N. Daubeniana, dwarf, blue. Tender night-blooming kinds: N. dentata, white; N. Omarana, magenta; Frank Trelease, dark crimson. Hardy kinds: N. chromatella, yellow; N. tetragona helvola, dwarf yellow; N. Gladstoniana, white; 'N. tetragona, dwarf white; W. B. Shaw, pink; N. Laydekeri rosea, dwarf pink; Wm. Falconer, dark red. Cultivation of water-lilies. (William Tricker.) Water-lilies or nympheas are among the most royal, gorgeous, diversified, and universally admired plants in cultivation. No class of plants in our public parks can compete with them in attracting the people. Moreover, America is the most highly favored country in the world for the cultivation of aquatic plants. Ours is the only country which can have so rich and continuous a display of aquatics in flower from April to October in the open without artificial heat. In parks and private gardens are to be seen, flowering early in spring, all native nympheas, and others from Europe and Asia. The species begin to flower in April and continue until early fall, when a number of the hardy hybrids continue to flower uninterruptedly until the end of the season. In the central states and southward, the hardy varieties decline when tropical weather sets in, and the nights and days are hot. In the eastern states, and especially near the coast, where the nights are cool, the season is much longer, and the color of some of the pink varieties is more intense. Following the hardy nympheas come the nelumbiums in all their oriental splendor, brightening the summer season, and bridging over the declining period of the hardy nympheas and the approaching season of the tropical nympheas which arrive at maturity toward the latter end of July or beginning of August, and continue until fall. Finally the grandest of all aquatic plants, Victoria regia, may be seen in America growing in a natural pond, and producing its chaste flowers as late as the middle of October. America is rich in native species of nymphea, and it is the only country which has native white-, pink- and yellow-flowered kinds. Of the American nympheas there are about five that are best known. The common white water-lily is Nymphya odorata. Its variety rosea is the Cape Cod pink water-lily. N. tuberosa (syn. N. Teniformis) is a white-flowered species, inhabiting the western lakes. The yellow kind, N. flava, is indigenous to Florida and other southern states, but is hardy in New Jersey and southern New York. Another southern kind is the white-flowered N. odorata var. gigantea. In addition to the above well-known kinds, there are several distinct forms and hybrids. The commencement of the cultivation of aquatics in America led to the commingling of species, especially of N. odorata and N. tuberosa. The result is that in several sections are to be found many similar varieties, and forms of both white and pink, some of which are valuable, being distinct in color and having large, handsome, fragrant flowers, while a host of others are worthless, so far as distinct varieties are concerned. N. tuberosa is known as the largest and purest white water- lily, distinct in foliage, flowers and rootstock. This species has proved to be the most susceptible of cross-fertilization. One great hindrance to the cultivation of such half-breeds, is that most of them produce seed. The seedlings are either white or pink, and seldom, if ever, like the parent plant. There are in different sections of the country distinct forms of N. tuberosa, some having long, narrow petals and slightly fragrant flowers, others again having broad incurving petals, forming handsome cup-shaped highly fragrant flowers; still others have very full flowers, quite double, the numerous petals crowding each other until the reflexed sepals inclose the stalk, forming spherical flowers like balls of snow. N. luberosa, in any of its forms, should not be planted in a small pond with other nympheas, for it is such a rampant grower that in a short time it will smother the less vigorous kinds. This species delights in plenty of space, and water 2 to 3 feet deep, with soil of a tenacious character. However, it will thrive in almost any soil, and is well adapted for naturalizing in lakes and ponds. Attempts at naturalizing or cultivating on a small scale have not been very satisfactory; but the species will well repay any extra care to establish it in desirable localities. Two or three species are indigenous to continental Europe, notably N. alba, the well-known English white water-lily, N. Candida, the white Bohemian water-lily, and N. alba var. rosea, the Swedish water-lily. The last named is the only distinct or true red-flowered, hardy species. Still another species, which has played a very important part with specialists of the present day, is N. tetragona (N. pygmaea), from China and Japan. Nymphaea odorata was introduced into England during the eighteenth century, and was probably the first foreign nymphea to reach that country. Other species followed later, mostly tropical; but, although the English people were ardent horticulturists and lovers of the beautiful in nature over a century ago, nympheas never became popular, and remained a neglected class of plants until a few years ago, when N. Marliac, of Temple-sur-Lot, France, conceived the idea of crossing the English white water-lily with the well-known Cape Cod pink water-lily, and tht Florida yellow variety. Nothing in the horticultural world has created more surprising results in the blending of the American and English species. These species have been the progenitors of numerous varieties, which have made this class of plants the most popular and desirable of all aquatic decorative subjects, and within reach of all. Their popularity has kept constantly increasing and ever heightened by new additions. America, also, has contributed its quota to the list of novelties, and some of these are unsurpassed by any European introductions. From the apparently simple conditions under which our native species are found growing, many amateurs have concluded that all these plants require is water and possibly some mud to keep the roots in. Many attempts have been made to grow these plants in pails and tubs, with inevitable failure as a result. Professional gardeners, also, have made grievous errors, for, while they have used every means to secure fine specimen plants of flowers, vegetables and luscious fruits, they have usually given meager attention to water-lilies, and have not supplied half their wants. Water-lilies, all nympheas, succeed best when grown, as near as possible, under their existing natural conditions; these are a rich alluvial soil in abundance, water, and clear uninterrupted sunlight. Where natural ponds exist these conditions are found, but often there is a deficiency of light, caused by shade trees. Let the trees remain, but choose open spots for the nympheas. They may be planted on the margins of sluggish streams, in bays and sheltered nooks. Where artificial ponds are used, the most satisfactory method is to build solid walls of reinforced cement, with a concrete bottom, provided with an outlet and overflow. In all cases make the pond as large as existing means will allow, not for a moment considering it possible to be too large. One method of providing for the sustenance of these plants is to place a layer of soil in the bottom of the pond from 9 to 12 or more inches deep. This will suit the plants admirably. Artificial ponds are usually constructed in a conspicuous spot, where everything is required to be well kept. In such situations it is necessary occasionally to take off some dead leaves, or cut a few choice flowers, and if they cannot be reached from the edge of the pond, the attendant must wade in after them. The result is that the water, which should always be clear, is muddy, and when it settles there is a muddy deposit on the leaves that makes them very unsightly. Moreover, this treading in the soft soil breaks numerous roots. To avoid these and other attendant evils, place the soil in boxes from 3 to 4 feet square, and 1 foot deep, and in these plant one single plant of the vigorous and moderate growers, allowing ample space between the boxes. One plant of any tropical water-lily in such a box, or three of smaller species, will require 50 to 100 square feet of water surface, as will also strong hardy nympheas, since these may remain two years undisturbed, although some of these are best replanted every season. The pond should be 2 to 2}-£ feet in depth. The soil should be a strong loam, the top-soil from a pasture composted with cow-manure in proportion of one-third. This should be prepared six months, at least, before planting time. This soil is suitable for all aquatic plants. In any case, when filling the boxes or placing the soil in bottom of pond, tread moderately firm and cover with an inch of sand. The water may be spring-water, rainwater or that from any available source. The clearest spring-water will soon turn green from exposure to the sun and air, but after fermentation settles clear. Do not place the plants in a newly constructed pond or basin immediately after it is finished, as the caustic property of the cement will injure the plants. Wash the new construction thoroughly and then supply it with clean fresh water. Planting of the hardy varieties may be done in April and May, according to the latitude and earliness or lateness of season. The conditions should be conducive to active growth at once. Tropical nympheas should not be planted until there is evidence that summer has come. Hardy nympheas may be planted in spring and summer (not in autumn); late planting is better than deferring till next spring, as the plants under such conditions will get established before autumn closes, and the plants will start naturally in spring, receiving no check. The above method of construction and cultivation is to be commended, but other methods are adopted with a fair degree of success, but with attendant evils which are discouraging and at times very annoying and costly. Tanks or artificial ponds may be constructed with cement, digging the pond the desired size, having sloping sides and afterward lining the same with concrete and finishing with a facing of cement. However, such a pond will not stand the effects of hard freezing weather even if protected; and what is worse, the new or freshly removed soil will settle during the season, and the pond is very likely to spring a leak. Another method of construction is to line the pond with well-tamped clay, from 4 to 6 inches thick, afterward covering with 2 inches of sand. The labor for such construction is expensive, however, the clay may not be good, and the pond is likely to be muddy; it is now better to build of cement. There are yet the advocates for tub-culture. Plants will grow in tubs, and as soon as the plant-food is exhausted, which is often at an early date, the plants exist awhile and then draw out a miserable, exhausted and discouraging career. Fountain basins are often made the receptacles for nympheas. There they may be grown if the right conditions are accorded them, but there must not be a stream or spray of water running all the time, as the water may be cold, chilling the plants and checking their growth. Nympheas have insect pests like other cultivated plants. Aphides are sometimes troublesome. The best remedy is their natural enemy, the "lady-bugs" or "lady-birds." A colony of these voracious insects makes short work of the aphides, as do also the lace-winged flies. An insect of recent acquaintance with nympheas is a leaf-miner, the larva of a small fly, which cuts channels through the leaf in all directions. Sometimes only a few of these are in evidence; at other times the leaves are fairly alive with them. The trouble is easily detected. A simple remedy is kerosene emulsion, applied with a fine spray at evening after the flowers are closed. Another troublesome insect is a leaf-cutter, Hydrocampa obliteralis (or proprialis). The larva cuts out pieces of the leaf and hides between two pieces, which makes a kind of tent. In this tent the larva moves about. At first it moves slowly, but as it nears maturity the larva becomes ravenous and then eats the surface of the leaves near the center, and cuts off much larger pieces of the leaf. The best remedy is a lamp trap for the mature insect. Frogs and dragon-flies will catch numbers of them. Arsenate of lead spray will destroy the larvae. Nympheas are also subject to a 'fungous disease, a leaf-spot which is easily discerned after a spell of warm, humid weather. The leaves are scorched and crumpled, the plant is denuded of its foliage; new leaves are weak and smaller, and so too are the flowers, if indeed there are any. This disease must be checked at once or the plants will be severely set back, if not ruined. A remedy is bordeaux mixture. Use a fine spray, and dilute the mixture to half the strength recommended for most plants. It is best to spray twice with a weak solution rather than to spray once with a too strong solution and to damage the foliage. A light dusting on the leaves with carbonate of copper will soon remedy the trouble. In winter, tender nympheas should be kept in tanks or tubs under glass. For hardy species, cover the tank with boards and pile on dry leaves, coarse hay or other material; or the roots may be taken out and buried in a sheltered place. Water-lilies in California. (Edmund D. Sturtevant.) The culture of nympheas in California presents fewer difficulties than in the eastern states. The varieties which are hardy in the East flourish equally well and bloom for a longer period. In frostless localities, especially where the lemon tree is free from injury, such tender varieties as Nymphaea devoniensis, N. dentata and N. zanzibariensis may be left in the open pond during the winter. In colder localities, the tubers should be removed to warmer quarters in November to remain until spring. If a greenhouse is not available, a small pool built in such a manner that it can be covered with hotbed sash will afford suitable protection. Very little room is needed for these when they arc dormant. The manner of cultivating both the hardy and tender varieties is much the same in California as in the eastern states. For growing a small collection, a pool 8 or 10 feet across may be made by excavating 2 or 3 feet, making the walls of concrete, brick or stone, and covering the bottom with concrete. The best quality of cement should be used for all the work. An overflow pipe should be put in and so arranged that the pool may be emptied when occasion requires. Basins 20 or 30 feet in diameter, or even larger than this, are desirable for growing a good collection. In a small pool, wooden boxes 10 inches deep and 18 inches to 2 feet square may be used to hold soil for the plants. In a large basin some of the boxes may be 3 or 4 feet square. While most aquatics will flower freely in contracted quarters, they will attain greater perfection and produce much larger flowers if they have abundance of room. Most of these plants are gross feeders, and it is well- nigh impossible to make the soil too rich for them. It is not necessary to go to a swamp or natural pond to obtain what is suitable. Any soil that will grow good vegetables will, if properly enriched, grow water-lilies. A compost, consisting of two-thirds good soil and one-third thoroughly decayed cow- or stable-manure, with a sprinkling of bone-meal, is recommended. A dark friable loam, which is intermediate between "adobe" and sandy loam, is desirable for this purpose. The tenderest varieties, such as N. devoniensis and N. dentata, will flower for a long period without any forcing; but if started into growth in March in a greenhouse or hotbed and planted in the pond in May, there will be a great gain in the length of the flowering season. The soil for the tender varieties should be renewed every year, and that for the hardy ones every two years. If aphides or the pest known as the leaf-roller make their appearance, the leaves, should be sprayed with kerosene emulsion very much diluted, using one part emulsion to fifteen of water. If large ponds or lakes with a natural earth bottom are used for growing water- lilies, care must be taken that noxious weeds do not get a foothold. Cat-tails (Typha latifolia) and tules" or bulrushes are troublesome if not destroyed when they first make their appearance. Palms, both fan-leaved and feathery, giant bamboos, musas, strelitzias, papyrus, giant grasses, fatsia and caladiums are among the things which can be used to ornament the surroundings of the water-garden. The genus Nymphaea divides itself readily into two main divisions, which again are subdivided into five subgenera as follows: Section I. Apocarpiae. Carpels free at the sides, united at their edges to the central column of the fl. and at their backs to the receptacle: outermost stamens ripening first, innermost last: rhizome ovate, stoloniferous.—Tender day-bloomers: fls. on strong scapes 4-12 or 14 in. above the water (Lytopleura, Casp.). Subgenus I. Anecphya. Stamens all slender, half as long as the petals, almost without any appendage (Fig. 2545): carpellary styles wanting: fls. blue, rosy or white.—Two species, in N. Austral. Subgenus II. Brachyceras. Outermost stamens with an appendage above the anther (Fig. 2546): carpellary styles short, triangular: fls. white, blue, pink or yellow.—About 15 species in the tropics all around the world. Section II. Syncarpiae. Carpels entirely fused together (Symphytopleura, Casp.). Subgenus III. Castalia. Sepals not evidently nerved: carpellary styles flat, linear: outer stamens petaloid: innermost stamens first to ripen, their filaments short, narrower or but slightly wider than the anthers (Fig. 2547).—Hardy or half-hardy day-bloomers: fls. white, pink, red or yellow. In the entire North Temperate Zone, excepting the Pacific slope of N. Amer. Subgenus IV. Lotos. Sepals prominently veined; a space between the insertion of the petals and stamens; stamens broad, flat, rounded at apex (Fig. 2548): carpellary styles linear: Lvs. sharply dentate: rhizome ovate, stoloniferous.—Tender night-bloomers: fls. red or white on strong scapes 3-12 in. above the water, opening on 4 successive nights. Two or 3 species in S. Eu. and Asia and N. and Cent. Afr. Subgenus V. Hydrocallis. Sepals not evidently nerved: carpellary styles long, club-shaped: petals in alternating circles of 4: stamens much as hi Castalia, all opening about the same time: rhizome ovate, stoloniferous.—Tender night-bloomers: fls. creamy white. About 9 species in Trop. Amer. The initial C in the synonymy-Castalia. The above text is from the Standard Cyclopedia of Horticulture. It may be out of date, but still contains valuable and interesting information which can be incorporated into the remainder of the article. Click on "Collapse" in the header to hide this text.

Nymphaea (pronounced /nɪmˈfiː.ə/) is a genus of aquatic plants in the family Nymphaeaceae. There are about 50 species in the genus, which has a cosmopolitan distribution. There are hardy varieties which grow to zone 1, and much more tropical varieties which cannot tolerate frost.

Cultivation

Make sure the depth of your pond is right for the particular variety you are planting. Protect more tender plants from winter cold by covering pond, adding water to give depth, or store the dormant tubers indoors in sand during the winter.