PGMS Member Area > PGMS Knowledge Center

Courtesy of National Garden Bureau

For centuries, Dianthus has been one of the most sought after plants for various landscapes. Its popularity comes in part from its ease of growing, but even more so from its palette of colors. Blooms present not only bright, solid colors—white, red, rose, dark red, lavender, pink, and the elusive yellow (D. knappii)—but also bicolors: picotees, with solid colors edged in white or a paler hue; “eyed” blooms with dark marks at their centers; streaks and multi-colored blooms on one plant.

Add foliage that ranges from bright green to gray-green, spicy fragrance in many species, and plant size that runs the gamut from petite 6-inch plants for edging a perennial garden, highlighting or a rock garden, to 3-foot specimens suitable for borders and cutting gardens, and you can understand why green industry professionals get excited about this variable genus. Read on about some of the more popular species and hybrids and how to raise them successfully in your landscapes.

THE NAMING OF PLANTS
The genus Dianthus contains about 300 species, but only a rather small number warrant attention. Dianthus, is from the Greek words for “flower of the gods” (meaning Zeus; Jove, or Jupiter, to the Romans). Dianthus is in the family Caryophyllaceae, a name derived from the Greek for clove tree, a reference to the often clove-scented blooms.

There are only four Dianthus species that are readily available for gardeners. Each is described below with a selection of varieties for reference.

* Dianthus barbatus (Dye-ANN-thus bar-BAY-tus) is the familiar sweet william of countless old-fashioned cottage gardens, a short-lived perennial or biennial. Newer varieties are annual flowering. The blooms of the species and many hybrids have a central spot, or eye. Native to southern Europe, sweet william is winter-hardy to Zone 4 and grows from 5 inches to 2 feet tall. Its single, sometimes double, flowers appear in dense clusters from late spring through summer. Flowers may or may not be fragrant. Some very old varieties still grace gardens, like the open-pollinated ‘Wee Willie’ which grows a petite 5 inches tall and produces early, single flowers. Other, more modern varieties range from the open-pollinated ‘Pinocchio Mix,’ a dwarf biennial, and the ‘Giant Imperial’ series, a tall biennial, to tall annual F1 hybrids such as the ‘Hollandia’ series and ‘Cinderella Mix,’ a hybrid for the cutting garden. ‘Amazon Neon Duo’ flowers are a 50:50 mixture of cherry and purple. The 18- to 24-inch Amazon does double duty as a perennial (Zone 5) and as a cutflower. ‘Noverna’ and ‘Heritage’ series are new, medium-tall annuals.

* D. chinensis (Chin-NEN-sis) a.k.a. China pinks, can be an annual or biennial or short-lived perennial (hardy to Zone 7), though all the best varieties or series on the market today will flower as an annual - first year from seed. Originally from China, plants tend to be dwarf, 6 to 10 inches tall, but may reach 18 inches. They produce single (occasionally double), small, scentless flowers intermittently all summer. These carefree plants need little maintenance; deadheading is not required for them to continue to bloom. The common name, pink, refers not to the color of the blooms but to their serrated edges; to “pink” (with slightly different spelling of pynken) meant to cut or notch in old-English—think of pinking shears. Actually, the word for the color pink comes from the name of the flower, not the other way around. Some of the best among open-pollinated varieties are ‘Persian Carpet,’ ‘Pastel Bedder’ and ‘China Doll’ (a 1970 All-America Selections Winner). Hybrids ‘Snowfire’ (1978 AAS winner), ‘Magic Charms’ (1974 AAS winner) and ‘Corona Cherry Magic’ (2003 AAS winner) offer F1 vigor and unusual colors. The blooms of the latter combine solid cherry, lavender with cherry center and tie-dyed lavender/cherry on the same plant for a striking show. ‘Raspberry Parfait’ as featured on the front cover, reaches a full sun garden height of 6 to 8 inches and spreads 8 to10 inches in USDA Hardiness Zone 5, AHS Heat Zone 9-1.

* D. chinensis x barbatus. One of the most common interspecific crosses, this group combines the best of both species. Hybrids from these crosses flower more freely and tolerate more heat and frost than either of the individual species. Blooms tend to be larger as well and appear in terminal clusters. Plants may be annual or biennial, but if you start them early enough indoors they will flower the first year from seed. ‘Ideal Violet’ with bright green leaves, won an AAS award in 1992. The ‘Ideal’ series contains 18 colors. Plants are heat and frost tolerant reaching 8 to 10 inches. ‘Ideal Cherry Picotee’ flowers are a bicolor design with a pink flower edge.

* Other interspecific hybrids. Because Dianthus species cross-pollinate so readily, they produce hybrids easily. Many hybrids have barbatus as one parent with the other parent unknown, except to the breeder. Interspecific hybrids may be annual, biennial, or perennial. They offer color all season on plants that flower freely and tolerate heat and tough situations. ‘Bouquet Purple’ is a prime example; excellent as part of a cutting garden or in a border, it produces tall, sturdy stems and lacy, lightly fragrant flowers. ‘Melody Pink’ (2000 AAS winner) is another; an annual bred to be a cut flower, it grows to about 2 feet but spreads to only 10 to 12 inches and produces clusters of single flowers. F1 ‘Dynasty Purple’ is a lightly scented double flowered Dianthus with a garden height of 18 to 19 inches.

MORE DELIGHTFUL DIANTHUS
There are six lesser-known species worth mentioning, but are not readily available. The best source for seed or plants may be mail order catalogs.

* D. x allwoodii (sometimes referred to as D. hybridus), commonly known as Allwood pinks, derived from crosses and backcrosses among a number of species, including carnation, cottage pinks and D. alpinus (the shorter hybrids). Compact and vigorous, they bloom off and on through midsummer, if you deadhead spent flowers. The flowers are fragrant; the foliage, gray-green.

* D. caryophyllus a.k.a. carnation or clove pink, includes the familiar florists’ carnations as well as border carnations. Hybrids are usually grown from cuttings, not seed, to retain uniform characteristics.

* D. plumarius commonly known as cottage pink, is a low growing, loosely tufted perennial, hardy to Zone 3. Both foliage and flowers are fragrant. An heirloom species introduced from Europe in Colonial days, it has single- and double-flowered forms. ‘Romance Mix’ produces single flowers in a wide color range; ‘Sweetness’ (Zones 4 to 9) flowers the first year from seed and bears some double flowers.

* D. chinensis ‘Heddewigii’ is a variety of China pinks, which blooms the first year from seed. An heirloom variety (listed in the Burpee Seed catalog back in 1888) it is very free flowering and produces double flowers.

* D. knappii flowers the first year from seed sown in early spring. Hardy to Zone 3, it is the only true sulphur-yellow species, flowers in summer and grows to 16 inches tall. ‘Yellow Harmony’ is a fine variety.

* D. deltoides commonly known as maiden pink, forms evergreen tufts or mats. Plants are very hardy (perennial to Zone 3). One of the few Dianthus to grow well in partial shade, it produces small flowers from summer to fall. Good for rock gardens and hillsides, cultivars include ‘Zing Rose’ and ‘Zing Salmon.’ ‘Confetti Cherry Red’ is a perennial in USDA Hardiness Zone 3-9, AHS Heat Zone 9-1.

* D. superbus, a.k.a. lilac pink, originated in Europe and Asia. A short-lived perennial hardy to Zone 4, it reseeds readily. Treat it as a biennial for best results. Flowering in summer, it produces deeply fringed petals, which are fragrant. ‘Crimsonia’ and ‘Primadonna’ are two cultivars on the market.

A BRIEF HISTORY
You need to go way back in history, to ancient Greek and Roman times in fact, to find the first references to Dianthus. Through the centuries, they traveled from Europe to England and eventually to colonial America, picking up a variety of intriguing names along the way. Known variously as sweet william, pinks, gillyflower, cottage pink, carnation and clove pink, Dianthus species became an integral part of gardens, due to their charming forms, colors and sometimes heady fragrances. People also used the flowers for flavorings, in wine, soups, sauces and jams. Because Dianthus cross-pollinates between species with ease in the wild and in the garden (like the orchid in that characteristic) connoisseurs had an abundance of different plants to select from.

Until the last century, Dianthus flowers had a much shorter season than they now do. In the late 1960s, a Goldsmith Seeds breeder, Charles James, crossed D. barbatuswith D. chinensis, in spite of Glenn Goldsmith’s warning that the cross would be unable to produce seed. Happily, he was wrong, and ‘Queen of Hearts,’ as the resulting plant was named, went on to win an All-America Award in 1971. This interspecific cross had many advantages. The chinensis parent line brought large flowers; the barbatus parent, hardiness and vigor. While the parent plant set seed, the progeny F1 hybrid plants were sterile and did not set seed. Because of this, the hybrid plants flowered freely all season. Many Dianthus species go to seed and stop producing flowers in midseason. Prior to this time, most Dianthus had a flowering season similar to candytuft, pretty but short.

Goldsmith followed up with another interspecific cross; ‘Magic Charms’ won an AAS award in 1974. Both varieties, but especially ‘Magic Charms,’ opened up the market for growers, who could now produce flowering bedding plants in pots or packs for spring which would go on to bloom all summer for the home gardener. Other interspecific crosses, by many companies, have followed in the ensuing years, some open-pollinated, some F1 hybrids.

SELECTING PLANTS AT THE GARDEN CENTER
You will find many different kinds of Dianthus at garden centers and nurseries, making it easy to find some to suit your needs.

* Look for plants with clear green or grayish green foliage. Avoid any with yellowed leaves (possible sign of root rot) and those that have traces of wispy webs, an indication of spider mites. Pass up leggy plants in favor of more compact or well-branched specimens.

* Many, but not all, plants will be in flower when you purchase them. Most will at least be in bud, and the buds may show some color. Pots of Dianthus usually contain plant labels indicating the variety name and, sometimes, its height and spread.

DIANTHUS IN THE LANDSCAPE
Dianthus lends itself to many design uses, depending on height and growth habit. Use dwarf and mat-forming Dianthus as an edging for a border, in containers, in a rock garden, among pavers in a patio, as a groundcover, or along a rock wall. Plant medium to tall varieties with other annuals and perennials in a border, in a cutting garden, and in front of evergreen shrubs. Combine Dianthus with plants that harmonize with its foliage and flower colors: for example, coral bells, feverfew, lamb’s-ear, larkspur, lavender, hardy geraniums, petunias, poppies, floribunda and shrub roses, and sage.

* To encourage continuous blooming or reblooming, deadhead (cut off spent blooms) regularly to prevent seed-formation. In a cutting garden, you promote new blooms each time you gather flowers for bouquets—an excellent cut flower, Dianthus lasts up to two weeks in a vase. After the first flush of bloom in late spring/early summer, lightly shear back both spent blooms and foliage of edging and groundcover plants.

* Many Dianthus self-seed readily, making even the annuals seem like perennials.

* Dianthus are shallow-rooted, so to insure the survival of the plants over winter, mulch lightly after the ground freezes in fall or early winter. If rabbits are rampant in your area, a mulch or covering of pine boughs may deter them from nibbling on the plants’ leaves, which tend to persist into winter, especially in the South.

* Most species of Dianthus can be grown for flower color through winter. Planting times range from September to November, depending on the area and fall temperatures. Start with plants from a garden center or plan ahead and sow seeds indoors or out.

* Although pests and diseases are seldom much of an issue for Dianthus, keep an eye out for signs of red spider mites and aphids. Wash the latter off with a hard spray; prevent the former by providing enough space for good air circulation among the plants and, if necessary, treat with an insecticidal soap. (Pesky rabbits may find the blooms and foliage less tasty.) When it comes to diseases, diligence is the best prevention. Plant in soil with good drainage, give plants sufficient spacing for air circulation, and immediately remove any plant parts or plants with signs of disease, such as watery stems (rot) or powdery coating on leaves (mildew).