Related species: Dianthus caryophyllus is the florist's carnation, which is usually greenhouse grown in conditions that are neither too hot nor too cold; D. barbatus is Sweet William, a biennial that sometimes lasts for several years; D. gratianopolitanus is the gray-green leaved mat-forming type that blooms once a year and is excellent in flower borders and rock gardens.
Dianthus pink is treasured for its grasslike, blue-green foliage and abundant starry flowers, which are often spicily fragrant. Depending on the type of dianthus pink, flowers appear in spring or summer and tend to be white, pink, red, rose, or lavender, but come in nearly all shades except true blue.
Dianthus superbus is a European/Asian loosely tufted species that typically grows to 8-12” (less frequently to 24”) tall with decumbent stems below and branched upright stems above. Shaggy, deeply-fringed, pale lilac flowers (to 2” across) appear singly or in pairs at the stem ends in summer.
A bit more tolerant of cold than others in the family, sweet William flourishes in U.S. Department of Agriculture plant hardiness zones 3 to 9. Generally, Dianthus are recommended for USDA zones 4 to 9. Reputedly, sweet William's short life may be due to its extravagance of blooms.