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.
When potted, plunge to the rims of the pots in coal-ashes, and give water sufficient to settle the soil about the roots, after which for the winter they will require little attention except that of giving air when the weather is mild, protection from severe frost, and a vigilant look-out for slugs, which are fond of nibbling the young tender corms. About February or March they will begin to move of their own accord, and if frame-accommodation may not be afforded them, they should be hardened off preparatory to standing out of doors in April or May, and plunged in a bed of coal-ashes in a well-sheltered, partially-shaded situation. One or two shifts may be necessary throughout the summer as the plants increase in size, but the shifts should be small. In October, if the pots are well filled with roots, the plants may receive a final shift and be stored away for the winter in the best manner the available means will allow, and in the following spring they should yield a reward for all this care and trouble in a plentiful crop of flowers.
The treatment for established plants does not consist of many details. Encourage vigorous growth for a couple of months after flowering is finished, remembering always that shade from mid-day sun is essential during this process; water abundantly, and keep clean, and in the end of September or beginning of October, before putting them away for winter, give a shift if required, but in any case examine the drainage, and repair it if necessary, and throughout the winter see that the roots do not shrivel for want of water. By these means, if carefully applied, ample success is certain. But those whose circumstances do not admit of such expensive and troublesome details should not be discouraged from the cultivation of Cyclamens. A few roots of flowering size of the hardy sorts may be procured and planted in September, in light rich soil, well drained, either on rockwork or in a warm sheltered border; and when spring comes round, protect the flowers from the inclement weather by the best means at disposal. The autumn-flowering species may be enjoyed with less trouble than those of spring, and do very well planted in the same way, but the cream of the gems is in the spring-flowering sorts.
It has to be added that, in planting or potting, the corms of those species, such as Cyclamen persicum, which are naturally large, should be inserted to such a depth as will bring their tops about level with the surface of the soil, and those naturally small should be slightly covered over with the soil. Nearly all the spring-flowering sorts will bear a little forcing, and by this means a welcome succession of flower may be kept up throughout the dreary winter months. The Cyclamen persicum sorts are best for this purpose. They bear extra excitement with less injury than most of the hardier species do.
Cyclamen Coum is a diminutive species, but also one of the earliest flowering, and consequently very desirable, though not one of the handsomest. The conns are smaller and smoother than those of the same age of most other species. The leaves are small, round, heart-shaped at the base, and entire on the margin. The corolla is small, bright red or purplish red, and divided into five ovate reflexed lobes. Flowers from February to April. Native of the mountains of the south of Europe at high elevations. Cyclamen Cyclamen Album is a very pretty variety of this species, and, flowering as it does at the same time, is an excellent companion to it. Cyclamen Cyclamen carneum is another interesting variety, with blush-coloured flowers.
Cyclamen Vernam has small corms. Leaves small, round, cordate at the base, and slightly notched at the point, the upper surface zoned with a band of pale green within the margin. The flowers are deep crimson, and appear in March and April. Native of the south of Europe at high elevations.
Cyclamen Repandum sometimes called ficariaefolium, is one of the best of the smaller-growing species. The corm is small. Leaves roundish, cordate, obscurely lobed, and minutely toothed. Lobes of corolla broadly ovate, bright red at the base, shading off into rose. Flowers in April and May. Greece. Rather a tender species, and very impatient of wet in winter.
Cyclamen Ibericiuu a very beautiful and distinct species. Leaves roundish, heart-shaped, sometimes toothed, often entire, and zoned irregularly with a band of greyish green. The flowers are large, variable in colour in shades of rose and white, but always marked at the base of the lobes, which are sharply lance-shaped, with a dark crimson or purplish crimson blotch. Flowers in March and April. Iberia.
Cyclamen Persicum though the tenderest, is one of the best. The corms are large. Leaves large, rather variable in form, but generally broadly ovate, with a deeply cordate base and slightly toothed margin, and more or less zoned irregularly with pale greyish green. Flowers large, dark red or crimson at the base of the lobes, which are white or pinkish white. Flowers in March and April. Cyprus. Cyclamen Coum hybridised with the pollen of Cyclamen persicum, by Mr Atkins of Painswick, produced the famous cross named Cyclamen Atkinsii, which for profusion of bloom, fine colouring, and amplitude of beautiful leaves, surpasses all Cyclamens. It has the neat compact habit of Cyclamen Coum, with greater luxuriance, and the large flowers of Cyclamen persicum. It is, however, more correctly a race than a fixed hybrid form that has resulted from this cross, and many of the varieties are beautiful in the extreme, though not very distinct one from another. Other varieties of Cyclamen persicum are Cyclamen persicum rubrum and Cyclamen persicum roseum, both desirable companions to the species.
This is a large-growing species with roundish heart-shaped toothed leaves, often zoned on the upper surface with pale green. The flowers vary in colour in different individuals, but in nature the most common colour is white or rose, or both shading into each other, but purple and various shades of red are also met with, and in cultivation there are varieties distinguished by different combinations of these colours. Flowers in August and September. Britain and other parts of Europe.
Cyclamen Liederifolium is perhaps, from the scientific point of view, not distinct from the last species, but the form usually vended under the name has distinctly angular leaves with a cordate base, and the flowers are lilac shading into rose. Flowers in August and September. South of Europe, usually in company with Cyclamen Europseum.
Cyclamen Neapolitanum is rather a variable species, and sometimes confounded with the two preceding. The leaves are most variable; but most commonly they are of the ivy shape, with a cordate base, and distinctly zoned on the upper surface. The flowers are dark red, shading into pink or pale purplish red at the tips of the lobes of the corolla. Native of Italy.
Cyclamen Littorale is a little-known species in this country. The corms are small. The leaves are roundish and cordate at the base, and prettily marbled on the upper surface. The flowers are bright rose; the lobes of the corolla short and broad. Flowers in March and April.