Calopogons - Fun Flowers

- by Carson E. Whitlow*

Calopogons offer a rewarding and enjoyable introduction to North American native terrestrials. This is especially true of Calopogon tuberosus and Calopogon pallidus. These sun-loving, multiflowered herbs are easily grown in a small area on the patio or porch, by the lily pool or anywhere else a 6- to 8-inch pot may be placed in full sun. However, the container's dimensions are not indicative of plant size. A 6-inch vessel can hold six double plants of Cpg. tuberosus easily. Ten- to 24-inch flower spikes of six to 25 flowers opening in succession during a period of several weeks are impressive. In Iowa, this begins in mid-June. Flowers ranging from 1 to 1 3/4 inches across, primarily in shades of lavender, compliment the grasslike foliage.

There are four species: Calopogon tuberosus, Calopogon pallidus, Calopogon barbatus and Calopogon multiflorus. Although I have only been successful growing the first two species, I refer to this genus as my fun flowers.

Calopogon tuberosus (grass pink) is the most widely distributed, growing in acid bog conditions from Nova Scotia and New England south to Florida and west to the states bordering the Mississippi River. Both plant and flower are smaller in the northern end of its range. Under cultivation, the northern clones bloom about two weeks before the southernmost clones, with generally fewer flowers. They also emerge a little earlier, seed pods dehisce in a shorter time and they enter dormancy weeks earlier than the southern clones. Flower color is reasonably constant. There are approximately four shades of lavender - vary pale to dark rose - and white.

The lip is the same color as the tepals. It has a hairy patch in the throat with three color areas which are in line from the end of the lip. There are usually yellow, white and darker lavender. The column is typically the same color as the base color, but it can be a dark lavender.

Fairly broad sepals are held quite flat. The petals, which are narrower and shorter than the sepals, are comprised of two lobes of equal length, with the lobe nearest the center of the flower fuller than the outermost lobe. The lip is narrow, enlarged at the end to triangular or rectangular in shape. This enlargement may vary to a degree and is absent in some forms.

Compared to other species, the leaves of Cpg. tuberosus are broad. The corm is usually fairly round, though it can be flattened and oblong. Blooming-size corms are one-half inch in diameter. Stronger plants have correspondingly larger corms and more flowers, up to 25 per specimen. Calopogon tuberosus var. simpsonii is reputed to be more robust and grows in alkaline muck in the south.

Calopogon pallidus (pale grass pink) is smaller flowered, rarely more than 1 inch across. The colors are usually pale, though darker shades occur and are of a different tone than those of Cpg. tuberosus. The lip coloration is similar in placement, but the colors also richer. The swelling on the end of the lip is more squarish, with the edges folded back and under. The petals are narrower and more linear than those of Cpg. tuberosus, and the ventral sepals are curved to some degree. The sepals recurve back from the flower; the petals are held forward.

Grasslike leaves may be up to 12 inches. A wiry 16-inch-long spike may carry up to 16 flowers. Each flower usually opens after the one preceding it is just about finished, creating a sparsely flowered appearance. The two-lobed corm is two-thirds the size of Cpg. tuberosus. Calopogon pallidus is a more southerly species than Cpg. tuberosus.

I have not been successful with the other two species. Therefore, I can only relate information from various sources (Luer, 1972; Correll, 1950). Of the two, Cpg. barbatus (bearded grass pink), found in damp pinelands, is more widely distributed, though more southerly and slightly more restricted than Cpg. pallidus. It is similar to Cpg. tuberosus, but one-half the size. In its native habit, Cpg. barbatus tends to bloom earlier than the other species and the flowers open in rapid succession, nearly all at one time. The cluster of five flowers is more compact. These traits would be desirable in hybrids.

Calopogon multiflorus (many-flowered grass pink) is centered mostly in Central Florida, where it grows in open pinelands and palmetto scrubs. The flowers are similar in size to those of Cpg. barbatus, are of considerable interest because the petals are also bilobed, but the larger part is on the outer lobe thus making the flower appear fuller. In addition, all flowers open about the same time in a compact cluster, thereby creating a superior display. The petal shape and nearly simultaneous flowering pattern are both important breeding considerations.

Growing Notes

Calopogons are easy to grow, both as mature plants and from seed, and require little space. For Cpg. tuberosus and Cpg. pallidus, the growing medium is equal parts silica sand and sphagnum peat moss.

Set corms 1 inch deep about one corm-size apart in a row in the ground or about the same distance apart in a container. Water thoroughly, and expect to see shoots in two weeks.

Locate Calopogons in full sun and keep moist. Under these conditions, strong new corms as large or larger than the original corms will form. Though fertilizing is unnecessary, an occasional application of a 10 percent 20-20-20 solution from early to mid- season is beneficial. Irrigate container-grown calopogons with rain or distilled water every few weeks to flush out accumulated fertilizer salts. Containers may sit in standing water, provided the vessels are tall. Wicked pots work also.

A dormant period during the winter is necessary. Remove the plants when the leaves die, the temperature dips to freezing, or allow the foliage to be frosted and then remove. This occurs in late October in Iowa. The old corm is usually brown and shriveled. Remove and discard it and the old roots. The newly formed corm will be at the base of the leaf and flower stem. Remove any debris and sheaths, and rinse and store in damp silica sand for the winter. Place a small handful of damp sand and two or more corms in a sandwich bag, seal with a twist tie and place in the crisper compartment of a refrigerator. A cup of moist sand is more than sufficient for a dozen corms. Remove from the refrigerator in early April and plant. A minimum three-month dormancy permits one to force them into flower early.

There are several reasons why artificially propagated and cultivated Cpg. tuberosus and Cpg. pallidus produce superior flowers and considerably larger corms than those of wild-grown specimens. There is little to no competition for nutrients in cultivation; preventing the development of capsules diverts energy into corm production; and artificial dormancy conditions reduce stress.


Calopogons are multiplied by dividing their corms. Secondary corms are often produced, especially on larger plants and those on which no capsules are allowed to develop. Permit capsules to form only when seed is desired or they will waste the plant's nutrient reserves.

It is possible to double the plants annually if the corms are fairly large, especially if the plant produced a secondary corm on its own the year before. A Calopogon corm has two "eyes" where new growth emerges. These are usually on opposite sides of the corm and can be located easily because of their lighter-green-to-white coloration that distinguishes them from the surrounding tissue. Cut between the two eyes with a razor blade to yield two equal vertical pieces. To reduce the chance of rot, adhere the halves: apply a small amount of super glue to the cut surfaces and press together. Both eyes will sprout and produce flowers, although there may be a decrease in flower number. However, these double plants will form two new corms, both usually the same size as the original. Allow for an extra half-corm space between each corm to prevent the plants from growing into one another.

Hybridizing Trends

Though Dr. Clark Riley (1983) has indicated the potential for the hardy terrestrial orchids, little has been done. However, there is considerable interest for developing these lovelies.

The first hybrid involving Calopogon was an intergeneric cross named Caloarethusa Poet's Song (Cpg. tuberosus x Arethusa bulbosa). It was produced by Robert Yannetti, who has been working with Aret. bulbosa to determine the genetics involved with lip markings and color patterns. He is also experimenting with Eleorchis japonica (see below) and Bletilla striata. Yannetti is finding that only about 20 percent of the seed-grown Aret. bulbosa that flower will bloom the following year. The remainder only bloom after another couple of years or disappear.

Calopogon Adventure (tuberosus x pallidus) bloomed for the first time in August, 1991. The flower, about the size of a smaller-flowered Cpg. tuberosus, was the common medium lavender. However, the lip was triangular and more richly colored. The petals were more linear and appeared fuller overall on the plant that bloomed, which seems an improvement. Fairly flat sepals complemented the petals which were slightly cupped forward. The ventral sepals were more curved than Cpg. tuberosus. Utilizing a pale pollen parent may reveal different color shades in the progeny. A second cross with a much darker form is expected to bloom soon, revealing new hues.

Yannetti went on to produce two more intergeneric hybrids, i.e., Elepogon Carson Whitlow (Elo. japonica x Cpg. tuberosus) and Elearethusa Trudy (Elo. japonica x Aret. bulbosa). Elepogon Carson Whitlow is very reminiscent of Clts. Poet's Song, but is smaller and often has two flowers.

Elearethusa Trudy looks much like a smaller Arethusa with good coloration. It also forms corms readily for the following year. This is especially important for continued breeding and commercial development.

Producing superior strains of the species now in cultivation is receiving attention. Selecting color forms, improvements in shape and floriferousness are prime concerns. Large quantities of wild-collected stock are not wanted because this would reduce native populations and delay the program since one to two years are required to establish and develop the corms. Instead, seed-grown plants achieve this in about the same time, with known parents and generally better results. However, collecting superior clones, color variants and clones possessing uncommon characteristics from wild populations to bring them into cultivation and expand the gene pool is desirable. Some may not approve of this, but in the long run, the cost to natural populations is considerably reduced.

The potential of Cpg. barbatus and Cpg. multiflorus has yet to be explored, and I welcome anyone in areas where they naturally occur to write me at the address below.

Though only four species of relatively limited variability comprise this genus, selecting new strains and developing hybrids will reveal new potential. Multigeneric hybrids will add to the excitement.


Correll, D.S. 1950. Native Orchids of North America North of Mexico. Stanford University Press, Stanford.

Luer, C.A. 1972. The Native Orchids of Florida. New York Botanical Garden, Bronx.

Riley, C.T. 1983 In Elmer H. Plaxton [ed.] North American Terrestrial Orchids, Symposium II, Proceedings and Lectures. Michigan Orchid Society.

* This appeared as an article in the American Orchid Society Bulletin, Vol. 61, No. 9, September, 1992, pp. 860-865. However, it has been updated to include some of the latest in hybridizing. See Arethusinae Hybrid List for other information.

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