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2004: The Year of the Dianthus |
The National Garden Bureau Celebrates 2004 as the Year of the Dianthus
For centuries, Dianthus has been one of the most sought after plants for the garden. As
an authority on annuals the National Garden Bureau found 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 a rock garden, or finishing off a container to
3-foot specimens suitable for borders and cutting gardens, and you can understand why
gardeners 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 own garden.
THE NAMING OF PLANTS
The genus Dianthus contains about 300 species, but only a rather small number
warrant the attention of home gardeners. Dianthus, variously known as sweet william,
pinks, maiden pink, and carnation, 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.
The National Garden Bureau notes 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. Sweet william does not refer to a person; the sweet
alludes to the plant’s fragrance; william comes from the mispronounciation, centuries
ago, of the French word for the flower: little eye, or oiellet. 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. While conducting research the
National Garden Bureau found they 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 20th century, however, most
selections were chance hybrids, courtesy of nature and of enthusiastic gardeners. The
characteristics of a particular plant were usually preserved through propagating by
cuttings and division. 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.
GROWING DIANTHUS FROM SEED
Most Dianthus grow easily from seed. Follow these easy directions to have many plants from
a small packet of seed.
Start Seeds Indoors
Plan to sow seeds 6 to 8 weeks before you want to plant them outdoors. Because Dianthus
withstands some cold, you can set them out in the garden at or just before the average
last frost date in your area.
* Fill a shallow container or a flat containing individual cells with a commercial
seed-starting (germinating) mix. Moisten the mix and let it drain.
* Sow the seeds in rows in the container or 3 to 4 per cell and cover the seeds lightly
with a thin layer of the germinating mix or vermiculite. Press the mix down lightly and
spritz the surface with water to moisten it and settle the seeds.
* Place the container in a clear plastic bag and tie it closed with a twist tie. Keep the
plastic off the surface by inserting three or four plastic plant labels, plant sticks or
twigs in the medium before enclosing the tray in the bag. Set in a warm location so the
medium maintains a temperature of about 70 degrees Fahrenheit.
* Seeds of annuals and biennials germinate in 7 to 10 days; perennials take a bit longer,
2 to 3 weeks. When you see the first greenery, remove the plastic cover and place the
container in a sunny, preferably south-facing, window or in a fluorescent-light garden.
* Keep the medium evenly moist, but not soggy. When you need to water, do so from the
bottom: Set the container in a sink or dishpan filled with 1 to 2 inches of water and let
the water soak in from below. Remove the container when you see moisture beading on the
surface. Do not overwater.
* Begin to fertilize with a water-soluble fertilizer about 10 days after seedlings appear.
Provide lights or a sunny growing location to avoid stretched, leggy plants.
* When seedlings in cells or individual pots have two sets of true leaves (not the first
cotyledon leaves), snip off all but the strongest plant. Snip off plants in the rows in
flats to space those that remain about 2 inches apart. Provide good air circulation by not
overcrowding the plants. Transplant seedlings to individual 2-1/2 inch pots when they have
3 to 4 sets of true leaves.
* Maintain even soil moisture and fertilize every 10 days to 2 weeks until you transplant
the seedlings outdoors. Maintain high light levels.
Sow Seeds Outdoors
Starting seeds indoors gives you the best chance for early and full bloom during the
summer, but you can also sow annual Dianthus, D. chinensis, and those treated as
annuals, D. barbatus for example, outdoors in spring after danger of frost has
passed. The National Garden Bureau recommends you sow seeds where you want the plants to
grow and cover lightly with fine soil or compost. Keep the seedbed evenly moist until
germination occurs.
Start biennial and perennial Dianthus anytime in spring or summer but at least two months
before the average date of the first fall frost in your area. Sow seeds in place or in a
separate seedbed or cold frame, transplanting seedlings to their final spot in the garden
the following spring.
SELECTING PLANTS AT THE GARDEN CENTER
If you prefer to begin your garden with plants, letting someone else take care of starting
the seeds, you will find many different kinds of Dianthus at garden centers and nurseries,
making it easy to find some to suit your design ideas and space.
* 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.
TRANSPLANTING
Pick a Site. Dianthus grow best in full sun, in a garden that receives at least six
hours of direct sun daily. Maiden pink and sweet william will tolerate partial shade, but
most Dianthus in shady locations produce fewer blooms on lankier plants.
Prepare the Soil. Dianthus prefer somewhat alkaline soil that drains well. If your
soil tends to be acidic, mix in ground limestone before planting. If you are starting a
new garden, dig the bed to a depth of about 6 inches and incorporate a one-inch layer of
compost or dried manure at the same time.
Transplant. Pick an overcast, calm day to transplant, whether you plant homegrown
or store-bought seedlings. Use a trowel to dig a hole, unpot the plant, and set it in the
ground at the same level it was growing in the pot. Firm the soil around the root ball.
Space dwarf varieties 6 to 8 inches apart, taller and mat-forming kinds about 12 inches
apart. Water the planting well when all the plants are in.
DIANTHUS IN THE GARDEN
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.
* In the Southeast and Southwest, gardeners can grow most species of Dianthus 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 from the
garden hose; 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).
POTTED DIANTHUS
Seemingly made for containers, the National Garden Bureau highly recommends gardeners use
Dianthus in pots and window boxes. Set the smaller and dwarf varieties along the edge,
taller varieties in the center or at the back of a container you view from one side only.
Mix and match them with any number of compatible annuals, perennials, and herbs, such as
argeranthemum, lavender, lemon thyme, nemesia, petunia and viola.
Planting: Select a container with drainage holes in the bottom or sides so the soil
does not become waterlogged. Use a packaged potting mix or a soilless mix; do not use
garden soil. Garden soil often contains weed seeds and is quite heavy when wet. If you
plan to move the container around or you plant a window box for a sill or deck railing,
consider using a soilless mix, which is lightweight. If you want to skip fertilizing the
plants during the season, incorporate a controlled-release fertilizer in the mix before
planting. To cut down on watering chores, mix water-absorbing polymer crystals in as well.
Before unpotting the plants, set them on top of the mix in the container and rearrange
them until you like the design. Then, unpot and place the plants in the mix at the same
level they were growing originally. Water the planting well.
Care: Check the soil in the containers frequently in very hot weather and water as
needed. Fertilize monthly with a water-soluble plant food, if you did not use a
controlled-release fertilizer at planting time. Deadhead spent blooms to encourage
reblooming.
Information and Photograph courtesy of National Garden Bureau.
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