This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
D. fruticosus is usually considered as a variety of the foregoing species. The Tree Carnations and most of the perpetual varieties come under this sub-species. The stems are half-woody at the base, and rise to a height of 3 to 6 feet when supported. The varieties are now becoming numerous, but they are more valuable for winter flowering under glass than for the flower garden. It is said to be of Eastern origin and a wild form. In the French edition this is held to be distinct from D. Caryophyllus.
2. D. plumarius. Pink. - A much dwarfer plant than the foregoing, forming dense grass-like tufts of a glaucous tint, and therefore well adapted for edging. Its flowering season commences about the middle or end of May, and is of about a month's duration. There are many varieties of it, mostly very fragrant, both double and single, white, rose, bright carmine, and some are laced or bordered with carmine or lake on a rose or white ground. For pot culture preference is usually given to the white varieties or those bordered with purple on a white ground. It is a native of the South of Europe.
3. D. barbatus (fig. 44). Sweet William. - This is indigenous in the central and western Pyrenees and other parts of Europe. It is readily distinguished from the preceding species by its broader oblong-lanceolate leaves alone, and also by the relative small-ness of its flowers, which by way of compensation are borne in dense corymbs. The date of its introduction to our gardens is so remote that it is difficult to find its origin in the old authors; but one thing is certain, that it is only within the last fifty years that the beautiful varieties now cultivated in our gardens began to arrive from Germany and Russia. Since then they have been considerably increased, and we might now enumerate upwards of a hundred, both double and single, and comprehending every shade and combination of colour from white and pink to dark purple.
Fig. 44. Dianthus barbatus. (1/3 nat. size.)
4. D. Hispanicus. Spanish Pink. - A charming variety of the Sweet William. It has rather broad leaves, erect stems, and dense inflorescence; but its flowers are at least three times the size of the common varieties. Their normal tint is a lilac carmine, with a circle of dots of a deeper colour around the centre. This colouring is greatly modified under cultivation, and varieties are now known some quite white, others rose or carmine, and others again marbled with pink or carmine upon a white ground. And it is not an unusual occurrence to meet with all these varieties of colouring in the same individual; hence, doubtless, its French name of CEillet badin, or Sportive Pink. Only the semi-double and double varieties are generally seen in gardens, and even they are not very widely spread at the present time, though they have long been in favour.
In the French edition this is given as a distinct species; but the true D. His-pdnicus is a totally different plant, belonging to another section of the genus. 5. D. Chinensis (fig. 45). Chinese Pink, or Indian Pink. - Brought from China early in the eighteenth century by a French missionary named Bignon, it soon became as popular as the other species of this genus. It is distinguished by its narrower more acute glaucous leaves and its incomparably larger flowers, which in some varieties are truly enormous. This, like all the other species, has been remarkably improved under culture, and has given birth to a multitude of both single and double varieties, self-coloured or streaked, white, pink, crimson, carmine, purple-violet, etc. Among these varieties we may allude more particularly to those of Heddewig, introduced from Russia a few years ago by an amateur of that name, remarkable alike for the size of their flowers and the beauty of their colouring. They have been divided into two groups: the Giant varieties (D. Chinensis giganteus), in which the peduncles are usually one-flowered; and the Fringed varieties (D. Chinensis laciniatus), with the flowers always large and often double, and petals deeply jagged or torn, giving them an unusual appearance in the genus.
Fig. 45. Dianthus Chinensis. (1/4 nat. size.)
Following these species, though less known and less generally cultivated, we may cite the Superb Pink, D.superbus (fig. 46), whose pink or carmine rather large flowers are fringed or deeply laciniated; the Virgin Pink, D. virgineus; the Deltoid Pink, D. deltoides; the French Pink, D. Gallicus; and the Shining Pink, D. fulgens, with crimson flowers : all natives of Europe, and which would doubtless produce many beautiful varieties with careful culture. D. caesius, neglectus, and aren-arius are some of the best species for rockeries.
As in most genera rich in species, those of the genus Dianthus readily cross, and, although gardeners have not proceeded here with more order or method than they have with Roses, there are several varieties whose hybridity can scarcely be contested. This is particularly the case with the variety called Flon, a very beautiful perpetual variety, found, it is said, amongst some seedlings of the Sweet William by a gardener of Angers, M. Flon, and from which another gardener, M. Pare, has succeeded in raising some new varieties. It is supposed that the plant which furnished the seeds was fertilised by the Carnation, or rather by the Tree-Carnation, a supposition suggested by the long duration of the flowering season of the species in question. This is invariably sterile, and the new varieties obtained from it - one white and one striped - were simply accidental sports, which have been perpetuated by propagation from pipings. Sterility, however, it should be observed, is not necessarily a proof of hybridity, because this is no infrequent consequence in double flowers. The Pink Flon is herbaceous and somewhat woody, forming thick spreading tufts, which throw up erect stems from a foot to a foot and a half high, terminated by large corymbs of double purple odoriferous flowers of medium size. It is very hardy.
Fig. 46. Dianthus superbus. (1/2 nat. size.)
An English gardener has described another hybrid, the issue of D. fulgens impregnated by pollen from a double Carnation. This hybrid is remarkable for its immense corymbs of very double flowers of the most beautiful carmine. More recently, several French florists have offered a third hybrid for sale, the result, it seems, of a cross between D. superbus, female, and a Japanese species, perhaps D. Chinensis,. male.