|Standard Cyclopedia of Horticulture|
House Plants are those plants that can be grown in the ordinary rooms of dwelling- houses. They may be hardy or tender; only such as are suitable for this purpose will be considered here.
In the living-rooms of the modern well-built house, plants must contend against difficulties which did not exist in the less carefully equipped dwellings of fifty years ago or earlier. The present methods of heating and lighting, by gas or kerosene lamps, not electricity, produce a dry atmosphere which is inimical to vegetable growth. In houses lighted by electricity, and heated by any system which introduces fresh air in abundance, the hindrance is not so troublesome. Too much heat and dry air are harder for plants to endure than insufficient light, but it is also lack of light which makes it difficult to grow flowering plants in houses. Dust and insects do harm, but can be checked.
For the above reasons it is important to choose house plants which are adapted to resist a dry atmosphere, a high temperature and inadequate light. Such examples can be found among certain tropical plants with coriaceous leaves and small stomata, what the florists call foliage plants, e. g., rubber trees, palms, and the like. These make the best foundation upon which any successful system of growing plants in houses can be built. Flowering plants can also be used, but they should be introduced from time to time, each in its proper season, when about to bloom or in bloom, and not considered a part of the permanent arrangement. After flowering they should be removed: their function is not unlike the use of cut-flowers, but they last longer and are not more expensive, while they largely increase the attraction of the window-garden.
The best rooms for plants are those which get the most sun, and the best positions are those nearest the windows, where there is not only more light but more fresh air. A large palm, fern or rubber will grow in an entry or poorly lighted corner, but the best place is that which is best lighted. Plants do well in a kitchen, the moisture from the cooking helping them materially; it is by no means a bad hospital for unhealthy specimens.
A conservatory is desirable but not always obtainable on account of the expense; it should agree with the architecture of the house and have the proper aspect. The construction should be durable, the walls and roof low and, a point often neglected, great attention should be paid to ventilation. This should be given not only in the roof, the very apex when possible, but also on the sides at the bottom. The trouble comes in early autumn when the plants are first potted up and again when the sun begins to be hotter in February, March and April. Fresh air should be given all winter on bright days, but it is particularly needed at the times named above. Shade is also advisable on warm sunny days and a system of screens either inside or out can be devised. The florists' method of painting the glass is good but unsightly. When a regular conservatory is unobtainable, a plantroom can sometimes be made which is most satisfactory and at comparatively small cost. It is often possible to utilize a part of the basement for such purpose. A southeast or south exposure is best, but if it faces southwest or even west no trouble follows. Such a room should be well furnished with windows which open both at top and bottom. The floor should be of concrete or porous tile and the walls covered with material which is unharmed by water; good drainage should be provided. Such a room is not only capable of keeping plants in good condition but can also be used for starting seedlings and cuttings. The temperature can be kept well above freezing and under 50° F. sometimes without extra fire heat when such a room opens into a heated cellar. It can be used not only for growing plants but also as a storeroom from which plants can be taken for decorating the living- rooms; there is no better place for all bulbous plants from the time they are taken out of the frame until they show flower-buds well developed.
In rooms in which plants are kept, any device by which the atmospheric moisture can be increased is desirable: oilcloth on the floor, or a floor of porous tiles: a zinc tray, in which the pots can be set and surrounded with moss; saucers under the pots, the pots being raised slightly to prevent the roots of the plants standing in the water which runs through. By these aids not only can plenty of water be given to the roots, but there will also be some opportunity to sprinkle the leaves, while the evaporation of surplus water will dampen the air. The Japanese porcelain pots are not only ornamental but useful; the glaze prevents undue evaporation from the sides, and the legs hold the pot well above the water which may collect in the saucer: they are in every way excellent. Wooden tubs are serviceable for large plants or for any which are likely to be exposed to frost, either before or after bringing into the house. Plants should never be overpotted, but the larger the bulk of earth the easier it can be kept uniformly moist; from the wider surface, too, there is more evaporation. For these reasons it is sometimes a good plan to have window-boxes in which several plants can be grown; or the boxes can be filled with moss in which the pots can be plunged. All pots, tubs or boxes for growing plants should have holes in the bottom through which water can pass freely.
Much trouble is likely to come from the use of unsuitable potting soil. Procure it from an experienced florist, or make it yourself of equal parts rotted sods, old leaf- mold, well-decayed cow-manure and clean, sharp sand: discard tea leaves, chip dirt, and the decomposed remains of dead stumps. The soil should always be moist when used, not too wet and never dry: it should be made firm, not hard, and a good space left between the surface and rim. Large pots should be drained with potsherds and moss. The best time for potting is just before the plant begins to grow; the next best is just before growth ceases, thus giving the plant opportunity to establish itself in its new quarters before it stops growing. It is not always easy to do this properly at home, and large and valuable plants should be sent to a florist. Plants growing in the open air should be lifted and potted two weeks or more before bringing into the house, not only before frost but before the nights are cool. Keep them at first in a shady place, gradually accustom them to the sunlight, and carefully avoid all drafts. Do not give too much water at the root: some wilting is unavoidable, and cannot be prevented by heavy watering. Give one good application when they are first potted, and sprinkle the foliage and surroundings in the middle of the day. After they are established, keep them out-of-doors, on the piazza or porch, until there is danger of frost, but try to bring them into the house before the furnace fires are lighted.
A period of rest is natural to all plants. Amateurs often make mistakes in trying to force plants to grow all winter in the house after a vigorous growth in the open ground all summer. Such plants should be rested, kept cool at first and water withheld, but never to such an extent as to shrivel the wood. No rules can be given for watering, the most important detail of plant-growing. Water must be given as it is required, a knowledge to be gained from experience only. This may be once a day or once a week, twice a day or once in two days. The smaller the pot and the more vigorous the growth, the oftener it will be required. In hot weather and in dry rooms more water is needed than in cool rooms and on damp, cloudy days. It should always be given in sufficient quantity to pass through the hole in the bottom of the pot: here it can remain an hour or more, and part of it will soak up, back into the pot, but the surplus should be taken away with a sponge, unless the pot has legs or it is a plant like calla, English ivy, or some ferns, which are uninjured by an over-supply. Water given to the foliage of house plants in the form of spray is always helpful.
Insects, dust and sometimes fungous pests are troublesome to house plants, due largely to insufficient watering and lack of ventilation. The best remedy is frequent washings with warm water and a sponge for plants with large leaves. All plants can be easily cleaned at the kitchen sink or in the bathtub, or advantage can be taken of a mild day, and the work done in the yard with the hose. The forcible application of water will remove most insects, but if scale appears it must be taken off with a stiff brush. Whale-oil and tobacco soap are too rank for house use; fir-tree oil and Gishurst's compound are less obnoxious. They can be used when the plants are washed with sponge or brush. The florists' preventive against greenfly is impracticable: enough tobacco smoke to harm them would not be tolerated in living-rooms. Tobacco stems may be burned, however, in the plantroom described above if a well-fitted door is provided and precautions a/e taken to make the ceiling air-tight. It is altogether too dangerous to use cyanide of potassium in any form of plant-growing in the house. The red-spider can be driven off by spraying with an atomizer, if discovered in time. Some plants are not attacked by insects, but are injured by dust, e.g., the rubber-tree. Dusting when dry is better than nothing, but washing is best. If fungous diseases appear, the plants should be isolated, giving a chance to recover, or be thrown away.
Ventilation is an important factor in keeping house plants in good condition. Open the windows on bright days: the fresh air is moist and therefore grateful, and will do no harm, even if the plants are near the glass, so long as the sun shines and discretion is exercised.
The night temperature need never exceed 50° F., and a drop of 5° or even 10° is not likely to do any harm. Precautions must be taken to exclude frost; the blinds must be shut and the curtains pulled down on cold nights. A layer of newspapers between the plants and the windows is a protection in extremely bad weather, or a large kerosene lamp can be allowed to burn all night near the plants.
A list of suitable foliage plants for the house: Ficus elastica, the rubber plant; F. religiosa (peepul tree) and most of the other strong-growing evergreen species. Livistona sinensis, Corypha australis, Chamaerops fortunei and Rhapis japonica, all good fan-palms (the first is the best); Phoenix reclinala, P. rupicola and P. canariensis are the best date-palms. Seaforthia elegans, Howea belmoreana, Kentia forsteriana, Areca baueri, A. rubra and Cocas weddeliana are all good palms, but require more care and heat than the fan- and date- palms. Cycas revolula (sago-palm), Curculigo recurvata, Aspidistra lurida, Pandanus ulilis (screw pine), P. veilchii, Phormium tenax (New Zealand flax), Cyperus alternifolius, Papyrus antiquorum, Cordyline, Dracaena, Agave americana (century plant), Pittosporum, Grevillea robusta, English ivy, wandering jew and some species of cactus all do well in ordinary rooms. Daphne odora, laurestinus, Olea fragrans and orange trees are both flowering and foliage plants, but require a cooler room than any of the preceding varieties.
Good flowering plants are Azalea indicts, and Camellia japonica, both of which should be kept in a cool room when not in bloom. Calla and begonia both do well. Chrysanthemums, cinerarias, gloxinias, gladioli, cyclamens, Chinese and English primroses, freesia, oxalis, fuchsia, mahernia, euphorbia, heliotrope, pelargonium and lily-of-the-valley can be brought into the rooms when in flower, and last a reasonable time in good condition. Hyacinths, tulips, narcissi and crocus, if potted in October, kept covered up out-of-doors until cold weather, stored in a cool cellar until the middle of January and then brought into warm rooms, will give flowers: a succession can be maintained by bringing them into warmth at intervals. (See Bulb.)
The following varieties of hyacinths and tulips are particularly recommended for growing in living- rooms under ordinary circumstances:
Hyacinths.—The single sorts are much better than the double and more easily handled. Single reds and pinks: Gen. Pelissier, Gigantea, King of the Belgians, La Victoire, Norma. Single white: La Grandesse, L'lnnocence, Madame Van der Hoop, Mr. Plimsoll. Single blue: Czar Peter, Enchantress, Grand Lilas, King of the Blues, Lord Derby, Queen of the Blues. Double red: Grootvorst, Lord Wellington, Noble par Merite. Double white: Isabella, La Grandesse. Double blue: Bloksberg, Garrick, Van Speyk. Double yellow: Goethe.
Tulips, early single.—Albion (White Hawk), white. Belle Alliance (Waterloo), red. Couleur Cardinal, bronze-red. Cramoisi Brillant, bright scarlet. Goldfinch, yellow. Keizerkroon, red and yellow. La Reine, white turning pink. MonTresor, yellow. Pottebakker, scarlet. Primrose Queen, sulfur-yellow. Prince of Austria, orange-red. Proserpine, carmine. Rose Grisde Lin, pink. Rose Luisante, deep pink. Thomas Moore, orange. Vermilion Brilliant, scarlet. Yellow Prince, yellow.
Tulips, double. — Couronne d'Or, yellow flushed red. Imperator rubrorum, red. Murillo, best light pink. Salvator Rosa, deep pink. Tournesol.yellow.
All' the Due Van Thol tulips are excellent for early forcing, particularly the scarlet. The Darwin tulips are now sometimes forced, but they are not suitable for growing in houses. The Parrot Cottage tulips and the like are not grown in this way.
Roman hyacinths are easily forced and with the Paper White narcissus can be flowered between Thanksgiving and Christmas. Narcissus Campernelle var. rugulosus, the Chinese sacred narcissus, the double Roman, and most varieties of Polyanthus narcissus flower earlier than the other sorts.