Dianthus are one of the most lovely yet underappreciated flowers in the spring garden.
Not only do they add color and fragrance, but they are among the best of the transition flowers, meaning they make their best show as the spring bulbs and other flowers are between seasons.
Dianthus comes from the Greek words meaning "flower of the gods." Dianthus is in the family Caryophyllaceae, Greek for "clove tree," which refers to the flowers' often clove-scented blooms.
The first recorded references to dianthus comes from ancient Greek and Roman writers. Subsequently, the blooms traveled to Europe, England and Colonial America, picking up many intriguing names along the way sweet william, pinks, gillyflower, cottage pink, maiden pink, carnation and clove pink.
Their charming forms, colors and heady fragrances invited their use for flavorings in wine, soups, sauces and jams. Dianthus cross-pollinates naturally between species, so connoisseurs had an abundance of plants. Until the 20th century, most selections were chance hybrids, courtesy of nature and enthusiastic gardeners.
The genus Dianthus is a diverse group of plants containing about 300 species, but only four are readily available for gardeners.
Dianthus barbatus sweet william is found in countless old-fashioned cottage gardens. It is usually a biennial in northern Utah and will overwinter in all but the coldest areas. Newer varieties are annual flowering.
D. chinensis or China pinks can be annual, biennial or short-lived perennials. All the best varieties on the market today will flower as an annual in the first year from seed. Originally from China, the plants tend to be dwarfed, 6- to 10-inches tall, but they may reach 18 inches.
They produce small, single or occasionally double flowers intermittently all summer. The common name, pink, refers, not to the color of the blooms, but to their serrated edges. (To "pink" meant to cut or notch in Old English.) The word for the color comes from the flower, not the other way around.
Excellent open-pollinated varieties include "Persian Carpet," "Pastel Bedder" and "China Doll." Hybrids include "Snowfire," "Raspberry Parfait," "Magic Charms" and "Corona Cherry Magic."
Fortunately, most of these hybrids and selections are hardy, so they do well along the Wasatch Front. These carefree plants need little maintenance; deadheading is not required to keep them blooming continuously.
D. chinensis x barbatus are common interspecific crosses. This group has some of the best plants for local gardens as they tolerate more heat and frost than either one of the individual species.
The blooms are larger and grow as terminal clusters. Plants grow as annuals or biennials, but if greenhouses start them early enough, they will flower the first year from seed.
These hybrids flower more freely than their parent lines. "Ideal Violet" is one of 18 different colors in the "Ideal" series. Plants reach 8 to 10 inches in height.
Other interspecific hybrids have barbatus as one parent while the other parent is unknown, except to the breeder. These interspecific hybrids are annual, biennial or perennial. They offer season-long color on freely flowering plants and tolerate heat and tough situations.
Selected varieties include "Bouquet Purple," an excellent cutting garden or border plant with tall, sturdy stems and lacy, lightly fragrant flowers. "Melody Pink" is an annual bred to be a cut flower as it grows to about 2 feet but spreads to only 10 to 12 inches. "Dynasty Purple" is a lightly scented, double-flowered dianthus that grows to 18 inches.
It's too late to seed dianthus in the greenhouse for spring planting, and garden seeding doesn't usually work. Fortunately, there are many kinds of dianthus at local garden centers. Select plants with abundant, clear-green or grayish-green foliage. Avoid plants with yellowed leaves as they may have root rot. Choose compact, well-branched specimens rather than leggy plants.Grow dianthus in full sun (a least six hours daily). Maiden pink and sweet william tolerate partial shade. Fortunately, for many Utah gardeners, most dianthus prefer somewhat alkaline soil. They do, however, need soil that drains well, so add coarse organic matter and prepare the soil well.
Larry A. Sagers is the regional horticulturist, Utah State University Extension, at Thanksgiving Point.