Carnations are members of the Dianthus family, which includes pinks and sweet william as well as the more well-known florist carnations. They are available in many colors and sizes. Some carnations have been bred to bloom on long stems for the cut flower market, while others have short, sturdy stems that make them strong perennials in the garden. Nearly all Dianthus flowers have a distinctive spicy clove-like fragrance. The flower mingles well in a bouquet, and in the garden, with other fragrant flowers. Dianthus are usually grown as perennials; some varieties self-seed and grow as biennials.
Sweet william (Dianthus barbatus) is a small dianthus, about 6 to 12 inches tall and 6 to 12 inches wide. Nurseries sell plants as perennials, or you can easily grow it from seed. Sweet william is a wild flower, and it will reseed itself in unmowed wildflower gardens. Plant sweet william in full sun or partial shade along borders and in beds, or use it in rock gardens. The small flowers are in clusters of pink, white, deep red and bi-colors. Sweet william blooms in the spring and early summer, and its pretty foliage stays attractive all season. Trim spent blooms to prolong the flowering period.
Grenadin (Dianthus caryophyllus) is the type of carnation most people are familiar with. It is popular as a long-stemmed cut flower, and it is used in bouquets, corsages, and for many florist purposes. These carnations are available in several colors. The foliage of grenadin carnations appears frosty, and it adds visual texture to any garden. Plants are about 12 inches tall and 12 inches wide, with flowers carried above the foliage. They require full sun. The soil must be well drained; grenadine carnations will not tolerate soggy roots. Colorful grenadin carnations will attract butterflies, as well as repel deer.
'Starlight' (Dianthus plumaris) are pure white carnations. The foliage is about 4 to 6 inches tall, and the flower stems are 15 to 20 inches long. This variety, when purchased as a perennial plant, will have few blooms the first year while it establishes a good root system. After that, the plants will produce large numbers of long-stemmed beauties. 'Starlight' carnations are fully double flowers with ruffled petal edges. Plant these carnations in full sun in well-drained soil.