Most cacti are easy to grow, requiring little care and enduring the heat and dryness of a living room much better than most other plants. Their requirements are ample drainage and open soil. Cactus growers usually make a soil by mixing pulverized plaster or lime refuse with garden loam, using about two-thirds of the loam. The very fine parts, or dust, of the plaster, are blown out, else the soil is likely to cement. They may be rested at any season by simply setting them away in a dry place for two or three months, and bringing them into heat and light when they are wanted. As new growth advances they should have water occasionally, and when in bloom, they should be watered freely. Withhold water gradually after blooming until they are to be rested.
Some of the most common species in cultivation are the phyllocactus species, often called the night-blooming cereus. These are not the true night-blooming cereuses, which have angular or cylindrical stems, covered with bristles, while these have flat, leaf-like branches; the flowers of these, however, are very much like the cereus, opening at evening and closing before morning, and as the phyllocacti may be grown with greater ease, blooming on smaller and younger plants, they are to be recommended.
The true night-blooming cereuses are species of the genus Cereus. The commonest one is C. nycticalus, but C. grandiflorus, C. triangularis and others are occasionally seen. These plants all have long rod-like stems which are cylindrical or angular. These stems often reach a height of 10 to 30 ft., and they need support. They should be trained along a pillar or tied to a stake. They are uninteresting leafless things during a large part of the year; but in midsummer, after they are three or more years old, they throw out their great tubular flowers, which open at nightfall and wither and die when the light strikes them next morning. They are very easily grown, either in pots or planted in the natural soil in the conservatory. The only special care they need is good drainage at the roots, so that the soil will not become soggy.
The epiphyllum, or lobster cactus, or crab cactus, is one of the best of the family, easy of culture. It bears bright-colored blossoms at the end of each joint. When in flower, which will be in the winter months, it requires a richer soil than the other cacti. A suitable soil is made of two-thirds fibrous loam and one third leafmold; usually it is best to add sand or pulverized brick. In fall and early winter, keep rather dry, giving more water as the plant comes into bloom.
Opuntias, or prickly pears, are often grown as border plants through the summer. In fact, all the family may be planted out, and if a number of kinds are set in a bed together, they make a striking addition to the garden. Be very careful not to bruise the plants. It is better to plunge them in the pots than to turn them out of the pots.
Caladium.—Tuberous-rooted, tender perennial plants used for conservatory decoration, and also for subtropical and bold effects in the lawn (Plate IV). The plants commonly known under this name are really colocasias.
The roots should be dormant in the winter, being kept in a warm cellar or under a greenhouse bench, where they are not liable to frost or dampness. The roots are usually covered with earth, but they are kept dry. Early in spring the roots are put into boxes or pots and are started into growth, so that by the time settled weather comes they will be 1 or 2 feet high and ready to set directly into soil.
When set out of doors, they should be protected from strong winds, and from the full glare of direct sunlight. The soil should be rich and deep, and the plants should have an abundance of water. They do well about ponds (see Plate X).
Caladiums are most excellent plants for striking effects, especially against a house, high shrubbery, or other background. If they are planted by themselves, they should be in clumps rather than scattered as single specimens, as the effect is better. See that they get a good start before they are planted in the open ground. As soon as killed down by frost, dig them, dry the roots of superfluous moisture, and store till wanted in late winter or spring.
Calceolaria.—The calceolarias are small greenhouse herbs sometimes used in the window-garden. They are not very satisfactory plants for window treatment, however, since they suffer from dry atmosphere and from sudden changes of temperature.