This section is from the book "The Florists' Manual", by William Scott. Also available from Amazon: The Florist's Manual.
To this genus belongs our divine flower, the carnation, which has been treated at length as its value deserves. D. barbatus is the well known sweet william, a splendid border plant while in bloom but not of any commercial value. Perhaps because seen too often in the humblest gardens, or for some reason not apparent, it is not a flower that can be used in the commonest bouquet, though in June and July it makes a splendid show of bloom of the richest tints and markings.
The seed of the sweet williams can be sown in May in a coldframe and when the plants are large enough transplanted into flats or placed at once in the borders where they are to flower. They will make fine spreading plants, and being entirely hardy will send up a mass of bloom the following spring. They are biennials, but a few straggling plants and flowers are often seen to survive two or three years.
The Dianthus Chinensis and its splendid varieties, Heddewigii and its many forms, are the most useful to the florist. They also are biennials but are invariably treated as annuals and sown every spring. For their culture follow instructions given under the heading Aster and you will have no trouble. They look well in either the mixed border or in a solid bed.