This section is from "The Horticulturist, And Journal Of Rural Art And Rural Taste", by P. Barry, A. J. Downing, J. Jay Smith, Peter B. Mead, F. W. Woodward, Henry T. Williams. Also available from Amazon: Horticulturist and Journal of Rural Art and Rural Taste.
Dianthus Caryophyllus - The Carnation - with its enormous blossoms of rose-color, scarlet, yellow, white, either in plain colors, flecked, blotched, or banded, makes always a fine appearance, while its exquisite perfume never wants admirers. This should be raised from cuttings rooted in sandy soil under glass, or by layers - the layers are the more sure. For these select stout branches on a well-matured plant. Omit watering the plant for a day, or until the selected branches have wilted a little - they will be less liable to break during the process of layering. Dig and stir the soil in the pot pretty thoroughly with an old fork. Then trim off all the leaves from the shoot or branch to be layered, except those at the tip. Cut half through the joint to be rooted, in a slanting upward direction, with a sharp penknife, and bend the branch, taking care that it does not break at the incision, till the joint lies more than an inch beneath the soil, and confine it there with a hairpin. Then cover with the loosened soil all but the last inch of the stalk, pressing the earth carefully and securely over all. Water the soil sparingly - there is always danger to carnations from over-watering - and in five or six weeks you may remove the young plants thus formed to separate pots.
Sand, garden soil and stable refuse, in equal proportions, is the best ground for carnations. Some cultivators mix a little salt, and others soot, or charcoal, with this compost. When the flowers are partly opened it is well to to strengthen their calyxes (which are liable to burst) with a slender rubber ring.
A few words now in relation to the insects that annoy the flower-fancier and often prove so destructive to parlor plants. Of these, the most to be dreaded is the red spider, a creature so minute as to appear like the merest brown speck to the naked eye, but when crushed shows its guilty color. When the foliage or young shoots look yellow and begin to curl, you may be sure this pest is eating the under coat of the leaves, and hiding in every crevice. Unless prompt measures are taken to "oust" him, every one of your plants is doomed. Some persons find syringing with carbolic soap-suds a sure death to this insect. Others recommend the same use of sulphur-water. But the old way of fumigation, by placing the plants under a barrel, together with a dish of burning tobacco stems and leaves, is always effectual. This also closes the career of [the aphis, or green fly, the mealy bug, and the brown scale. But the smoke must be nearly strong enough to suffocate human beings, and the plants, after being confined in it an hour, look pitiful enough.
It is better to try drowning first; and so having prepared a quantity of warm suds in a large deep vessel - a bathing tub or something similar - cover the surface of the soil with a circular piece of pasteboard fastened on with a stout cloth bandage, to prevent dislodgment of the soil by the water, and lay the pot lengthwise therein. Every part of the plant must be completely submerged, and remain thus half an hour. Except in the worst cases, this effects a cure. Yet, after all, the old adage, "An ounce of prevention is worth a pound of cure," is amply proved in the case of plants. A careful washing of them once a week with a hit of sponge or a soft tooth brush, particularly the under surface of the leaves, and every axil which syringing may not reach, if your room be well ventilated - its atmosphere moist and temperate - will insure freedom from their depredations. The ground aphis sometimes preys upon the roots of verbenas, causing the plant to appear as if mildewed. Those insects are destroyed by washing the soil with a tepid decoction of tobacco, about the color of strong green tea, every day for a week or ten days.
The importance of guarding plants against the extremes of heat and cold has been stated; but if, by any accident, they become frost-bitten, they may be restored by immersing them immediately, while they are stiff, in cold water, and keeping them thus in a darkened room for an hour or two.