This section is from the book "The Gardener V1", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
Many elaborate directions for the preparation of Roses for pot-culture are given by various authorities, but they all resolve themselves into two principles - to get strong plants, and to place them properly in the strongest mass of soil in a given bulk. It has been already intimated that the Rose upon its own roots is the only legitimate form for growing in pots. Let such, then, be obtained, healthy and well developed, with three or four leading shoots and abundance of fibrous roots; we have next only to procure the pots and compost. Proper Rose-pots are differently shaped to the ordinary kinds; they are widish at the bottom, so as to hold the greatest possible quantity of earth. Choose them large and clean, and then make ready your favourites' food. The best method of draining the pots is to place an oyster-shell over the hole in the bottom, and to fill up for 2 or 3 inches with knobs of charcoal and broken bones. These are much better than potsherds, inasmuch as they afford a certain amount of nutriment, as well as serving for filtering purposes. Over these should be arranged some lumps of half-rotted turf from a fat loamy pasture, well saturated with liquid manure, the remaining compost being a mixture of hearty loam, somewhat rough, and well-decomposed manure.
Pot firmly, but not adhesively. It is surprising how the roots will multiply and spread in such a mixture, supplying abundant foliage above, and in due season a copious produce of well-developed blooms. The operation being completed, the plants may be consigned to a pit or the greenhouse; or, if such accessories be not at command, they may be set on a bottom of coal-ashes, and plunged in cocoa-nut refuse, with hoops placed over, so as to allow of mats being used as a protection, when necessary, from the frost; this latter operation, however, is only necessary in case of tender kinds. - The Gardeners' Magazine.