Gomphrena — An Antidote for the Late Summer Garden Blahs

• By Pat Chadwick
• /
• September 2017-Vol 3. No.9
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• 7 Comments

Keeping the ornamental garden looking fresh and colorful can be challenging in late summer and early fall. Hot, humid temperatures and lack of rain can linger well into autumn, stressing even the best-maintained garden. Summer-blooming perennials are generally done by now and the fall-blooming perennials are just getting started. Fortunately, a number of drought-tolerant annuals can help bridge the gap. Zinnias, marigolds, annual salvias, cosmos, floss flower, or cleome are all tough, dependable, drought-tolerant annuals. But if they seem common and ho-hum to you, perhaps Gomphrena (pronounced gom-FREE-nah) will be more to your liking.

Gomphrena, commonly known as globe amaranth, is an old-fashioned cottage garden plant. Although perennial in USDA zones 9-11, it must be treated as an annual north of Zone 9. A source of constant bloom from early summer until frost, it is at its most glorious in September and October when it is loaded with masses of blooms. This low-maintenance annual was born for hot, dry weather. In fact, its reputation for being able to withstand blistering high temperatures may have inspired the whimsical notion that it was originally planted at the gates of Hades. Now that’s hot!

A native of Central and South America, Gomphrena has been planted in ornamental gardens for centuries. Although not native to this country, it has a long history of use in North American gardens.  Introduced in Europe in 1714, this plant found its way to Virginia as early as 1737. John Custis grew it in his Williamsburg garden that year. Thomas Jefferson first planted the seeds at Shadwell, his boyhood home, on April 2, 1767. It continues to be grown at Monticello to this day and is one of the most asked-about flowers in the Monticello gardens.  

Huge Gomphrena Display at Monticello

Besides being a charming ornamental plant, Gomphrena is reputed to have a number of beneficial health benefits. Practitioners of folk medicine claim that is has antibacterial, antifungal, antioxidant, detoxifying and purifying properties. It has long been used in folk medicine to treat a variety of illnesses such as diabetes, coughs, and urinary retention. Of its many purported health benefits, it is perhaps best known historically for its use in treating hypertension. Modern-day clinical research appears to support its therapeutic use for this purpose.

DESCRIPTION OF GOMPHRENA SPECIES

Magenta Gomphrena Display

Gomphrena is one of 90 related species belonging to the Amaranth family. Gomphrena globosa is the species most commonly grown in this country.  It is a 12” to 24” tall annual bedding plant with stiff, jointed, and branched stems that give the plant a bushy appearance. Its 4” to 6” oblong leaves grow opposite one another and are slightly hairy looking when they are young. The 1” to 2” globe-shaped flower heads resemble clover blossoms and appear on upright spikes from summer until frost. The individual flowers within the flower heads are inconspicuous, but the stiff, papery bracts that form the flower head of the species and its cultivars are quite colorful and come in shades of white, pink and purple. The eye-catching magenta color is the most popular variety among gardeners. Because the blossoms dry well, this plant is often described in plant catalogs as an “everlasting.”

Orchid Pink Gomphrena Display

Gomphrena haageana, an amaranth species that is closely related to G. globosa, bears the distinction of being native to North America. Commonly referred to as Rio Grande globe amaranth, this tender perennial species is native to Texas, New Mexico, and Northeastern Mexico. It holds up particularly well in windy sites and blistering heat. Although closely related to G. globosa, this taller, lankier species with bright orange bracts averages 24” to 30” in height. Its true flowers are tiny, insignificant yellow trumpets that are best appreciated when seen close up. Crosses between G. globosa and G. haageana have significantly broadened the color palette to include white, pale pink, orchid pink, rose, lavender, magenta, purple, orange and red.

GOMPHRENA HYBRIDS AND CULTIVARS

Starting in the 1990s, plant breeders began paying more attention to this old-fashioned plant and embarked on a number of hybridizing programs. Field trials conducted by Mississippi State University, Louisiana State University’s Hammond Research Station, and Cornell University in Ithaca, New York, among others, resulted in the identification of a number of superior cultivars now available to the public.  ‘Lavender Lady’, ‘Ping Pong Purple’, ‘Pink Zazzle’, and ‘All Around Purple’ are just a few of the many excellent cultivars or hybrids to choose from. A few other Gomphrena choices include:

• ‘Bicolor Rose’ – This charming selection, also known as ‘Audray bicolor rose’, is a cultivar of G. globosa. It has dusty-rose bracts that fade to white at the top of each bloom.  At 36” tall, ‘Bicolor Rose’ is one of the tallest of the Gomphrena cultivars.
• ‘Strawberry Fields’ – This is the most common cultivar of G. haageana.  It produces large, brilliant orange-red bracts with tiny yellow flowers resembling strawberry seeds on 1’ to 3’ plants. You may either love or hate the bright orangey-red of this plant.  It’s all a matter of personal preference.
• ‘Fireworks’ – This G. globosa cultivar is unique in that it has large, looser-looking, hot pink blooms tipped with bright yellow stamens that are particularly interesting when viewed up close. The dramatic plants are 3’ to 4’ tall and wide, much larger than the common species.  This impressive, award-winning plant was named a Mississippi Medallion plant in 2010.  The gardening staff at Chanticleer Gardens in Wayne, Pennsylvania teamed this taller, wispier form of Gomphrena with wiry-looking Verbena bonariensis in their cut flower garden for a truly captivating display of color and texture.
• ‘Buddy Series’ – This dwarf, 8” to 12” tall and wide, mounded G. globosa cultivar series is available in three colors: ‘Buddy Purple’, ‘Buddy Rose’, and ‘Buddy White.’ This shorter form is best used at the front of the border. While it is recommended as a dried flower, it has short stems, which may make it more difficult to create a bouquet.
• ‘Gnome Series’ – The densely-branched, compact members of this G. globosa series grow only 6” to 10” tall and are suitable as edging plants or as a mass planting.  This series is available in purple, white, or orchid-pink.
• ‘Quality-In-Seed (QIS) Series’ – This series, with its G. haageana parent, adds carmine, red, and orange to the mix of available Gomphrena colors.  The stems tend to be long and strong, making them an excellent choice for a cutting garden.

HOW TO GROW GOMPHRENA

Select a sunny site for Gomphrena.  It can tolerate some shade but will flower best in full sun.

Once established, this easy-to-grow plant is low-maintenance, drought-resistant, and heat-tolerant.

Plant in moist but well-drained soil. While it will survive dry soil, Gomphrena appreciates being watered periodically during very hot, dry weather. When preparing the soil for planting, incorporate some compost.  As long as the soil is moderately fertile, Gomphrena doesn’t require much, if any, fertilizer.  Just don’t over fertilize.  Otherwise, the plant will push out a lot of foliage but few blossoms.

Sow the seeds directly in prepared garden beds after soil temperatures warm up in the spring. The seeds need temperatures of 70°F to 75°F to germinate. Or, if you prefer, start seeds indoors approximately 6 to 8 weeks before the last frost date.  Seedlings generally emerge in about 14 to 21 days.  If you’re an impatient gardener, speed up germination by soaking the seeds in warm water for a day or two before planting them. Once the seedlings are large enough to plant, harden them off and plant outdoors after the last frost date. Some sources indicate that Gomphrena seeds have a low germination rate, so you may want to plant more seeds than you need.

Some of the taller cultivars may need to be staked to keep them from falling over. To avoid this problem, pinch back young plants when they are about 6” tall. Pinching encourages a bushier habit and more flowers. Cutting the flowers often encourages more blooms, but deadheading is not necessary.

Gomphrena is generally free of pests and diseases, although it may occasionally be bothered by powdery mildew, gray mold, and fungal leaf spots during prolonged, cool, damp weather.

Deer typically leave this plant alone but butterflies like it.

USES FOR GOMPHRENA IN THE LANDSCAPE AND ELSEWHERE

Although not native to North America, neither the Gomphrena species nor its cultivars are invasive or aggressive. They may self-seed, but not extensively, and seedlings are easily removed if not wanted in the garden. A native of hotter climates, it holds up very well in Virginia’s hot, humid summer weather and is a source of brilliant color in the late summer-to-fall garden. For season-long color, use the plant in:

• Annual beds. Gomphrena can be very impressive when displayed as a mass planting of one color or in a couple of shades of the same color, such as purple and lavender-pink.  It also combines well with other annuals, particularly those with contrasting colors. The purple cultivars, for example, contrast well with yellow flowering annuals. The pink or rose cultivars contrast nicely with dark purple or burgundy coleus foliage.
• Borders. Depending on the cultivar, plant shorter selections at the front of the border and taller ones in the middle of the border.  Spiky-looking annuals, such as ‘Victoria Blue’ salvia or Celosia, provide a nice contrast to the bushy form of the Gomphrena.
• Container gardens. The taller selections can serve as an accent plant or “thriller” in a sunny container garden. The shorter selections serve as an excellent “filler” plant.
• Cutting gardens. Gomphrena makes an excellent cut flower. When used in floral arrangements, the blossoms last about a week.  As a bonus, the cut flowers sometimes take root in the vase.
• Cottage Gardens. Gomphrena combines well with other annuals and perennials in an informal setting such as that found in many cottage gardens.
• Rock gardens. Because this plant is very heat tolerant, it’s a good choice for the hot dry growing conditions generally associated with rock gardens.
• Dried flower arrangements, potpourri, or craft projects. The colorful bracts hold their shape and color well when dried and will last for several years. To dry blossoms, cut the flower stems when the blossoms are at their peak.  Remove foliage, bunch the stems loosely, and hang them upside down in a warm, airy place out of direct sunlight for about 2 to 3 weeks to dry.

Whether you choose the classic Gomphrena species or one of the many hybrids and cultivars that are available, this useful plant will please you with its cheerful, long season of colorful blooms and easy maintenance.  It’s a tough plant that will keep on blooming through the hottest summer weather well into fall.

SOURCES

The A-Z Encyclopedia of Garden Plants (The American Horticultural Society, 2004)

The Art of Gardening, Design Inspiration and Innovative Planting Techniques from Chanticleer (Chanticleer Gardeners, 2015)

The Southern Gardener’s Book of Lists (Chaplin, Lois Trigg, 1994)

The Gardener’s A-Z Guide to Growing Flowers from Seed to Bloom (Powell, Eileen, 2004)

“An Ethnobotanical Survey of Medicinal Plants in Trinidad,” National Institutes of Health, U.S. National Library of Medicine website (www.ncbi.nlm.nih.gov/pmc/articles )

“Phytochemical Screening and Evaluation of Cytotoxic, Antimicrobial and Cardiovascular Effects of Gomphrena Globosa L. (Amaranthaceae),” Journal of Medicinal Plants Research Website (academicjournals.org/journal/JMPR)

“The 2009 Cut Flower Trials,” Wien, H.C., Cornell University Department of Horticulture Report (www.hort.cornell.edu/wien/cutflowers/reports )

“Cut Flower Cultural Practice Studies and Variety Trials, 2012,” Wien, H.C., Cornell University Department of Horticulture Report (www.hort.cornell.edu/wien/cutflowers/reports/2012)

“New Gomphrena Varieties Offer More Landscape Options,” Owings, Allen, LSU AgCenter Horticulturist (New Gomphrena Varieties)

University of Wisconsin Extension Garden Fact Sheet, Globe Amaranth

Cornell University Growing Guide for Gomphrena

Monticello Garden Website www.monticelloshop.org

Missouri Botanical Garden Plant Finder, Gomphrena globosa

Missouri Botanical Garden Plant Finder, Gomphrena haageana