This section is from the book "The Gardener V2", 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.
A beautiful genus of succulent plants, forming splendid specimens in a short time, when a little attention can be devoted to them. The flowers, which are produced in large clusters on the points of the shoots, are singularly shaped and brilliantly coloured, and a large well-trained specimen in full flower is a rather conspicuous object in the greenhouse or conservatory.
The best time to propagate them is in July and August, selecting cuttings from shoots which are not showing flower, as there are always a few of these to be found on large plants. The strongest of the cuttings should be inserted singly into 60-sized pots, and three or more of the weaker ones in a 4-inch pot, in a compost of light loam, leaf-mould, and a good addition of sharp sand, the pots having previously been carefully crocked, with a layer of moss or rough fibry material placed over them. They should then be placed in a cold frame on a bed of ashes, and watered so as to wet the whole of the soil in the pots, after which keep close and shade carefully for a few days during the middle of the day when the sun is most powerful. In such a place they will emit roots and fill the cutting pots in a very short time, when the shading should be dispensed with. After they are well rooted they should be shifted on into pots two or three sizes larger than those they were struck in, draining them well as before, and giving them a nice rich loam with a fair proportion of sand and broken charcoal; or where the latter cannot be procured, a few bricks or potsherds broken very small and mixed with the soil will make a good substitute.
After this shift, any of the shoots that are likely to take the lead should have their points pinched out, to encourage lateral growths. This may be done up to the end of September or beginning of October, when it must be discontinued till the following spring. The greenhouse or Melon-house will be a suitable place to winter them in; and great care must be taken in watering them during the dull dark months of winter, giving just enough to keep them in a sweet healthy condition, and by no means practise the drying-off process, or they will shrivel and lose a lot of their bottom leaves, which spoils the look of the plants, besides injuring their constitution.
By February they will begin to grow, and if desirable can be encouraged with a little heat, and by the middle or end of March they will require another good shift, when the shoots should be nicely regulated and tied out to neat stakes. They will now need plenty of water, with a little liquid manure occasionally in a very weak state; and if desirable they can be gradually hardened off and stood out of doors in the open air during the summer months. The next shift will be into their flowering pots, which must not be deferred till too late in the season; and the plants must also be housed in good time, although we have invariably noticed the colour come much finer and brighter when allowed to partially open their flowers in the full sun out of doors. At the same time they must not be allowed to get wet, or the quality of the flowers will be injured; and when under cover, the flowering period can be greatly prolonged by a slight shade. There are a great many varieties of this elegant genus, but for general decorative purposes the old coccinea stands unrivalled.
A few cuttings struck and grown on annually will keep up a better succession of bloom than troubling with the old plants after they have flowered; and we would strongly recommend them to all lovers of greenhouse flowering-plants.