This section is from the book "How To Make A Flower Garden", by Wilhelm Miller. Also available from Amazon: The Well-Tended Perennial Garden: Planting and Pruning Techniques.
As tub plants the tender nymphæas are disappointing, because they are such rampant growers and feeders that, when confined to the limits of an ordinary tub or half-barrel, they are soon starved almost to death. The small quantity of plant-food is soon exhausted; the leaves assume a sickly yellow-green colour; and tubers are actually found in summer, when the plants should be in vigorous condition and producing flowers in abundance. If tubs are used at all, have such as will measure three or more feet in diameter.
The wonderful sustaining power of Victoria regia. Missouri Botanical Garden St. Louis.
Anticipate the wants of the plants, and if the plants are vigorous give them a liberal supply of liquid manure occasionally. They revel in our warmest summer weather, and are quite at home in the Victoria pond at a temperature of eighty-five to ninety degrees. Many failures occur through early transplanting. The check caused by digging, shipping, etc., which cannot be avoided, together with the change of temperature and exposure, are responsible for numerous losses which the vender is unjustly expected to shoulder. The proper time to plant nelumbium tubers is when the prevailing conditions of the weather are conducive to immediate growth. Bear in mind that tender nymphæas do not start into growth with the hardy kinds, and require different treatment.
A small water-lily pond in a suburban yard at Bond Hill, near Cincinnati.
Victoria regia is, indeed, the "royal" water-lily, and, under proper conditions, is of easy culture. It is not a native of North America, and cannot be grown as a hardy water-lily. It requires artificial heat. Some growers believe the Victoria can be grown in a natural pond as well as a tender nymphæa, but very few if any such cases are in evidence. The first on record was grown in North Carolina, and even there it was not safe to plant before the latter part of June. Occasionally plants will succeed in aquatic basins in and around Philadelphia without artificial heat, but the seasons are uncertain, and the results may more frequently be failure than success. In localities where the summer days and nights are hot, as in St. Louis, Victorias can be grown successfully without artificial heat. In altitudes where cool nights are experienced in summer, it is useless to try to dispense with artificial heat. The only royal road to success with Victoria regia is to grow it in an artificial pond where heat may be applied during the early season. A temperature of eighty-five to ninety degrees must be maintained.
By the end of June matured plants are in evidence, which will withstand a lower temperature with impunity; but, as a rule, we have warm weather during July and August, and the plants continue growing and flowering. The end of June is about the right time to plant Victoria regia without artificial heat, but it will be August before the plants arrive at maturity, when the season is also well advanced.
Another view of the same pond.
Victoria Trickeri succeeds best in a temperature ten degrees lower than V. regia, and is often difficult to raise. It is ruinous to seedlings, if they are at all late, to try to force them. The growth will be soft and liable to attacks of plant-lice, and when plant-lice take up their abode on a young leaf and remain unmolested the plant is soon crippled for life. The seed of V. Trickeri germinates in a temperature of from sixty-five to seventy-five degrees, and seventy-five to eighty-five degrees is the limit. Every precaution must be taken against greenfly, and there must be an abundance of light and ventilation as long as the plants remain under glass. Plants may be set out in the open with more certainty of success than with V. regia, but seldom before the end of June. However, if a temperature of seventy-five can be assured before then, it is safe to plant out Victorias. When an artificial temperature of eighty degrees can be maintained, even if it is by the middle of May, plant out in summer quarters, and by the end of June it will be safe to remove all protecting devices, such as steam pipes, frames, or sashes.
Nymphæas, nelumbiums and Victorias are the favourites, but there are numerous other plants that deserve attention and which add considerably to the general appearance of a water garden. Where an assortment of nymphæas is planted, the tender or tropical varieties break the monotony by throwing their flowers well above the foliage, although this feature is objectionable to some because it is so unlike the habit of our native pond-lilies. Something strong-growing and tall is really needed. Clumps of papyrus can be grown on the margin of the pond. Their tall, graceful plumes are unequalled by any other aquatic or subaquatic plant. The umbrella plant, Cyperus alternifolius, is another useful plant. The hedychium, or butterfly lily, with its canna-like foliage and white flowers, is worth growing; also the giant arrow-head, Sagittaria Montevidensis, Sagittaria falcata, and Jussiœa longifolia are very desirable plants. These are all tender, and need the protection of a greenhouse or warm shelter in winter.
Among hardy plants I would mention Sagittaria Japonica ft. pl.t Acorns Japonicus variegatus, Typha latifolia, Pontederia cordata, and Lythrutn roseum superbum.
A few of the minor aquatic plants may also find shelter in the large aquatic basin, but they must be watched carefully, for, although they are diminutive, they are rapid growers, soon interfering with the development of the nymphæas if not kept in bounds. The water hyacinths, Eichhornia crassipes major and E. azurea, are more curious than beautiful. The water-poppy, Limnocharis Humboldtii, is a Very striking yellow flower, and blooms profusely, but it grows prodigiously, and will soon fill a pond. The water-snowflake, Limnanthemum Indicum, is another very attractive plant, with pure white flowers covered with hirsute glands, giving it the appearance of a flake of snow. Like all limnanthemums, or "floating hearts" the flowers are produced on the petioles near the leaf; after several flowers are produced, a runner with another leaf and bunch of flowers follows, and so on, and very soon a large surface is covered. These and many other plants are interesting, but because of their wild and rambling habits I prefer to keep them out of the pond where choice nymphæas are grown.
Under side of a Victoria leaf, showing the beautiful venation and the spaces where air is held.
A very useful and desirable plant to grow, and one which can be had in flower in winter in a small space, is the cape pond-weed, Aponogeton distachyum. It is perfectly hardy, and one of the first to put in an appearance in spring, but during hot summer weather it is liable to rest. The flowers are white, borne on a forked spike, and very sweet-scented.
I may also mention here another tender aquatic plant that is travelling northward and proving itself hardy, and where so it is liable to become a pest, viz., the parrot's feather, Myriophyllum proserptnacoides. When grown in a large tub on a pedestal or a vase, where its branches can droop over the edges, it is a handsome plant; but on the margin of a pond, stream, or ditch, where the ground is wet or water shallow, it is of marvellous growth. The reason why these plants are seldom seen in such a luxurious condition is that people attempt to grow too many plants in a small pond or even in a tub, and consequently they are starved.
Many other plants that are subaquatic are deserving of general culture, but as yet are rarely seen in the garden, their proper place being the "bog garden."Many odd and curious yet beautiful plants are met with in this group - sarracenias, or pitcher plants, the Darlingtonia Californica, Drosera or sundew in variety, the marsh marigold (Caltha palustris), and its double form, the dainty myosotis, or forget-me-not, Menyanthes trifoliate, Calla palustris, Helonias bullata, Lobelia cardinalis, spireas in many forms, Calopo-gons, and the queen of hardy orchids, Cypripedium speciabile. Ferns, too, are capital for such places. The "bog garden" seems to be an English idea, and a good one, too, but we have never heard of any notable example of it in America.