University of Vermont Extension 
Department of Plant and Soil Science

Spring News Article

YEAR OF THE DIANTHUS

Dr. Leonard Perry, Extension Professor
University of Vermont

The National Garden Bureau is a non-profit organization that nationally recognizes and promotes worthy annual flowers and vegetables.  Each year they feature one of each in particular, and this year their flower choice is the dianthus.  This is also one of my favorite annual flowers, having a range of bright colors, great habits, attractive and sometimes fragrant leaves, and withstanding some cold.

Dianthus flowers come in solid colors of white, red, rose, lavender, pink, and even yellow.  They also come in bicolors.  These may be "picotees" with solid colors edged in white or paler tints.  These may be "eyed" with darker centers.  Or these may have streaks or several colors on one plant.

Leaves of dianthus range from bright to gray-green, and may have a clove scent in some. In fact this clove scent gives rise to one common name, clove pink.  Dianthus is also in the carnation family (Caryophyllaceae), the scientific family name coming from the Greek for clove tree. 

Varieties range from about 6-inch tall edging plants for borders or in pots, to 3-foot tall plants to mix in borders, or use separately in a cutting garden.  While many varieties are annual, living only one year, other species may be biennial or perennial. 
Dianthus were grown two millenia ago by the Greeks and Romans.  Over the centuries they moved to Europe, England, and then colonial America.  They picked up many names including pinks, gillyflower, cottage pink, clove pink, and sweet william.  The most popular florist cut flower, the carnation, is also a dianthus.

The name "pinks" is interesting in that it doesn't refer to the color, but rather to the notched edges of the flower petals.  This comes from the old English "pynken", as in pinking shears.  In fact, the name for the color pink first came from these flowers. 

Until the late 1960's, annual dianthus set seed, so only flowered for a short period.  It was then that the breeder Charles James developed a hybrid between two species that didn't set seed, so bloomed all season. His variety 'Queen of Hearts' won an All-America Award in 1971, and another similar hybrid 'Magic Charms' won an award in 1974.  These were the forebearers of the annuals we grow today as bedding plants. The most common you might find and grow fall into four groups.

The most common dianthus is probably the sweet william (Dianthus barbatus) as seen in cottage gardens. The "sweet" refers to the fragrance, and the "william" comes from a centuries old mispronunciation of the French word for the flower.  Although native to southern Europe and winter-hardy to USDA zone 4, most modern varieties are less hardy.  They range from dwarf biennials (two year life cycle, often blooming the second year) such as 'Pinnochio Mix', to tall annuals such as 'Hollandia.'  'Cinderella Mix' is a tall annual for cutting.  'Amazon Neon Duo' is a medium tall mix of cherry and purple for borders, for cut flowers, or to grow as a tender perennial.

China pinks (Dianthus chinensis) also is either an annual, biennial, or tender perennial (zone 7) depending on variety.  Most you may find though will bloom as an annual, the first year from sowing seed.  These originally came from China, hence the name, and generally tend to be a foot or less high.  They are low maintenance, don't need deadheading (flowers removed) after bloom, and bloom all season in many colors.  A couple of recent All-America winners are in this group-- 'Corona Cherry Magic' and 'Raspberry Parfait.'

Then there are the hybrids of these first two species, which have the best traits of both parents.  They may be annual or biennial.  Flowers tend to be larger.  Plants tolerate more heat and frost than either parent.  The "Ideal" series is the most popular of these hybrids, coming in 18 colors.  'Ideal Violet' won an All-America award in 1992.  'Ideal Cherry Picotee' has bicolor cherry flowers with a pink edge.

Finally there are the many other hybrids of species, resulting since these plants cross among themselves so readily.  Many of these have sweet william as one parent, and the other may be unknown, or known only to the breeder.  These bloom all season, and vary from medium to tall.  'Melody Pink' was an All-America winner in 2000, and at two feet tall is a good cut flower. 

You may sow dianthus indoors 6 to 8 weeks before planting outdoors.  Since they withstand some cold, you can plant outdoors just before or on your average last frost date.  If buying them, avoid leggy plants, indicating too little light or improper culture.  Similarly, avoid any with yellowed leaves that may be malnourished or have root rots. Place in the garden where they'll receive at least six hours daily of direct sun for best growth and bloom.

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