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.
These are very important adjuncts of the plant-house in winter; indeed, indispensable. The best kinds for winter work that I have met with are S. splendent and S. Gesneraflora; the S. fulgent may also be added. For winter blossoming, these are valuable, and their culture very simple. They should be propagated annually by cuttings in March, got speedily into small pots, and receive high culture in the greenhouse or a frame. In order to render them bushy, they must be frequently pinched; and, indeed, this pinching may be continued up to the end of June, when they may be allowed to form heads for blossoming. They may be flowered in seven-inch pots in perfection, although it is very convenient for some purposes to have a lot in five-inch pots also. By the middle of June they should be placed out of doors in cinder ashes in a very sunny situation, as they abhor shade, and all they require during the summer is regular watering. In the end of September, they should be placed in a cold frame for fear of frost, or, if room, on the front shelf of a greenhouse. No pinching may be allowed after this. A few remarks concerning soil are necessary.
Most of the Salvia family run too much to leaf, and are apt to become long-jointed. Now, the elements that conduce to this habit are rich soils, too much air moisture, and a want of light. These evils, therefore, must be avoided. For compost, nothing is so good as a plain, strong loam; this, with sound drainage, will be found to grow them shorter-jointed, and more compact, and will enable them to withstand an hour or two of drought without suffering. In all their stages they require full exposure to sunshine, and, when approaching the blooming condition, simply a cool and an airy situation in the house.