Taken from Eclectic Gardener @ http://www.teachinggarden.org/
Written by Alan Hickman

In 1797, when the monumental Gardener's and Botanist's Dictionary by Philip Miller was published, nine pages were devoted to the genus Dianthus. 'Dianthus Jove's-flower, or divine flower; from the fine colour and odour of some species.'
Miller named and described thirty species of Dianthus but he cautioned that the genus was a 'most inextricable botanical labyrinth.'After two hundred years of discovery, research, comparison and debate, the number of Dianthus species considered horticulturally significant is now close to fifty. There are innumerable crosses between the species and, according to The International Dianthus Register, the number of named cultivars runs over 30,000
2004 being the year of the Dianthus, a look at what all these plants have in common is perhaps appropriate. For a start they all have five petals - the single flowers as they are found in the wild that is - and they all have ten stamens. The leaves are usually bluish/greyish green, narrow and parallel sided, ending in a point. The leaf joins the stem in a bulbous node with the leaf wrapping around the stem like a sheath.
With one exception, all the Dianthus species have flowers either white or some shade of red. The exception is Dianthus knappii which is yellow. In the florist's trade the colour range is artificially extended by the practice of dipping the cut stems into dye. The famous green carnations worn by Oscar Wilde were produced this way.
Almost all the Dianthus species originate in a broad band which stretches across the Old World from Europe to Japan with the greatest concentration of species around the Mediterranean. The slopes of Mount Olympus are carpeted with all manner of Dianthus, thus the association with Zeus and the epithet 'flower of the gods'.
As a group, in the wild, Dianthus are plants of mountainsides, of open slopes and of fast-draining meadows. Just a few, such as D. barbatus and D. deltoides, can also be found growing in open sunny woodland.
In cultivation it can be taken as a rule-of-thumb that Dianthus should have a free draining, gritty, not too fertile soil in full sun. A trace of alkalinity is also appreciated. If it can be found, a bit of old broken-up wall plaster mixed in the soil will do the trick nicely. The one thing Dianthus will not tolerate is wet feet. Dianthus which are in waterlogged soil over winter are guaranteed to rot and be dead by spring.
From a gardener's point of view, Dianthus can be divided into two groups: Those which take a lot of care and those which don't. The species which originate in the lowlands tend to be tall and lax. In the wild they have the support and protection of grasses and other meadow herbs, but in the garden they usually need staking to stop them flopping about. The yellow flowered D. knappii definitely belongs to this group. Most of the cultivars of D. caryophyllus, the presumed parent of all the plants sold by florists as long-stemmed carnations, also belong to the group of fussy plants. For enthusiasts, these cultivars produce some of the most beautiful, sweet-smelling, flowers grown but they demand care and attention like any prima donna. There are beautiful cultivars of D. caryophyllus which are spectacular for the front of a mixed border, but they need to be carefully chosen for height, otherwise they will get too tall and just flop.
In the 'carefree'group are the low mound or mat forming alpine and sub-alpine Dianthus species. D. aplinus has been called 'the glory of the race.'Single, scentless flowers up to 4 cm in diameter can completely cover the low-growing mat of dark green foliage. D. arenarius makes an effective ground cover after a few years and will tolerate at least some amount of shade. D. deltoides is the parent of a multitude of named cultivars and is considered among the easiest of the Dianthus genus to grow. Although in the wild they are associated with dry chalky hillsides, in cultivation D. deltoides will put on a good show at the front of almost any reasonably sunny, reasonably dry flower border.
Right now, in the dead of winter when it's freezing cold and dreary, is the perfect time to go visit a grower and to see the range of Dianthus and other plants which will be available come spring. In Brampton we are fortunate to have an operation like Humber Nurseries Ltd., Hwy. 50 just south of Hwy. 7, which maintains a perennial stock year round. A walk along the plant benches in the vast cool greenhouses will give a glimpse of the outdoors two months from now. Full-time staff have the time to talk and one can browse and read the plant labels without being jostled by the hordes of May.