Easy culture and a lavish show of long-lasting flowers have made cymbidiums favorites with gardeners and commercial cut-flower growers alike. Standard cymbidium hybrids produce multiple 3- to 4-foot flower spikes from February to early May (some as early as Christmas), and each spike may contain as many as thirty 4- to 5-inch flowers. The flowers have a heavy texture and last well on the orchid, for 8 weeks or perhaps more. As the cut flowers are similarly durable, cymbidiums rival cattleyas in popularity as corsages.
The orchids have tightly clustered egg-shaped pseudobulbs clothed with the bases of the gracefully arching strap-shaped leaves. Unlike many orchids, cymbidiums are handsome plants even when out of flower. All are natives of a range from Japan and India to Australia. The large-flowering kinds are native to high, cool mountains and need cool nights to produce flowers. In warm-summer, cold-winter regions, grow them outside and bring them indoors before the first frost.
Smaller Chinese and Japanese species, grown in Asia as potted plants for centuries, are gradually gaining recognition elsewhere. A few dwarf species have been instrumental in producing miniatures and hybrids with hanging flower spikes. Some of these species are warm growers that can flower without the cool nights required by the large flowering kinds.
The aforementioned “easy culture” does need some qualification: for one thing, the large standard cymbidiums so popular as outdoor container plants on the Pacific Coast need low night temperatures to initiate flower buds. High daytime temperatures do not disturb them so long as they are not allowed to become sunburned, but nighttime temperatures should not exceed 60°F (16°C) in the fall.
Then too, from March to October, while new growth develops and matures, these orchids need frequent watering. After that their water supply may be reduced, but low night temperatures of about 45° to 55°F (7° to 13°C) remain necessary if the plants are to flower.
The plants themselves are hardy to 28°F (- 2°C), but their flower spikes are more tender and can be destroyed by frost. When low temperatures are predicted, move outdoor orchids beneath a deep overhang or into a garage or shed or else cover them with cloth or plastic, making sure that the material does not touch your orchids.
Many potting mixtures are available for these terrestrial orchids. Most are based on fine-grade fir bark blended with moisture-retaining elements such as peat moss, leaf mold, or sponge rock; some incorporate fertilizers. The most important factors in any mix, though, are fast drainage yet good water retention. Pots should, of course, drain freely. Clay pots are satisfactory, but plastic pots with drainage holes on the bottom and sides are widely used because their weight doesn’t add to that of the plants, which can become very large.
Cymbidiums should have enough light during the growing season to produce yellowish green foliage. If the foliage is dark green or bluish green, your light is inadequate, and your orchids may fail to flower satisfactorily. Where plants are hardy, grow them outdoors under lath or in light afternoon shade. Many people report successfully growing plants at the edge of east-facing porches, where they get full morning sun and modified light the rest of the day.
These orchids are heavy feeders: give them a complete liquid fertilizer every 2 weeks from January through July, cutting back to once a month from August through December. Slow release fertilizers will reduce your feeding chores; use them according to the package instruction.
Because cymbidiums flower best when their roots are crowded, transplanting is necessary only when the pseudobulbs begin to crowd the edge of the pot. The best time to transplant is just after flowering. Remove the orchid from the old container; if it proves difficult to slip out, invert the container, hold it by its edges, and tap it firmly against a sturdy table, bench, or fence rail. Sift the old bark or mix out of the roots, cut off any dead roots, and trim back live roots to half their original length. If you wish to divide orchids at this time, cut through the rhizome with a stout knife or pruning shears, leaving at least three leaf-bearing pseudobulbs in each division. Do not use a pot several sizes larger when transplanting; instead, select one that will allow no more than 2 or 3 inches between the leading edge of the plant and the side of the pot. Remember, you want to maintain those somewhat crowded conditions.
Add moistened bark or mix to the pot, tamp it down, and then hold the orchid in position with one hand while dropping mix down the sides with the other. Position the orchid to allow space for the leading edge or growing point, and continue to add bark, tamping it firmly around the roots. Water lightly until new growth becomes evident; then resume watering and feeding on your regular schedule. Be sure to sterilize your tools before-and after-cutting any orchid tissue.
Leafless pseudobulbs, or back bulbs, may be used to start new orchids. Each will have a small bud at its base. Stand this bulb upright when it develops visible growth. Then plant it in potting mix with the new growth at soil level. The bud will develop slowly into a foliage fan. With care, you will have another flowering plant in 2 or 3 years.
- Cymbidium canaliculatum
- A plant with rigid, thick leaves and clustered pseudobulbs. Long, arching stems bear many 1 1/2 in (4 cm) flowers with brown, purple or dull red sepals and petals with a creamy white, red-marked lip. Recently, a variety of pure green petals and sepals and a contrasting white lip was brought into cultivation in Australia. This is an attractive flower. It is being propagated and should become more readily available. In nature, C. canaliculatum shuns moist coastal and mountain areas and is found in the drier western side of the Great Dividing Range down the eastern coast of Australia. This flower is typically found on partly hollow branches or on rotten logs with the roots penetrating these and not exposed. Its habitat is low rainfall areas in good light and often in full sun. In cultivation, this species is best treated as an epiphyte, with the same potting medium as for cattleyas and drying the medium out between waterings. The orchid must have strong light and infrequent watering during the winter months.
- Cymbidium devonianum
- This species is found growing as an epiphyte or lithophyte in the Himalayan foothills. This orchid has wide, leathery leaves with little in the way of a pseudobulb and to the uninitiated, it might not be recognized as a cymbidium when not in flower. The pendulous flower stems bear 1 1/4 in (3 cm) flowers in shades of green, red and brown. The inflorescence will grow down well below the bottom of the container and, in common with most pendulous cymbidiums, the pot must be suspended when the plant is in flower. Again, in common with the others, no attempt should be made to stake the flower stems upright when they are developing. They will not elongate in this position, resulting in short stems and bunched flowers. C. devonianum can be cultivated similarly to other cymbidiums. It is not a large plant and appears in the ancestry of many miniature cymbidiums.
- Cymbidium finlaysonianum
- Long (to 4 feet) sprays of tawny red flowers droop from this warm-growing native of the Philippines.
- Cymbidium insigne
- This orchid native of China, Vietnam, and Thailand has yard-long leaves and flower spikes rising nearly 5 feet; its 4-inch flowers are white or pale pink, spotted with red. A cool grower, it is a parent of the large standard hybrids.
- Cymbidium lowianum
- Similar to C. insigne in size and coming from the same region, this cool grower has large, arching spikes of green flowers with red markings. It is another important parent of the modern hybrids.
- Cymbidium madidum
- Native to Australia, this warm grower has 2-foot clusters of brown or green, highly fragrant, inch-wide flowers. This orchid has been used in breeding hanging-basket hybrids boasting flower clusters up to 4 feet long.
- Cymbidium tigrinum
- One of the smallest orchids in the genus, being about 8 in (20 cm) high, with wide leaves and small, round, clustered pseudobulbs. It is another member of the genus which does not look like a typical cymbidium when not in flower. The short flower stems bear about three 2 in (5 cm) flowers which are dull, yellowish-green with a white lip. The flowers are more interesting than the description of them might suggest. This species is a cool-grower and can be cultivated in all respects like standard cymbidiums. Flowers open in late spring. There are a few attractive hybrids with the white lip often predominant.
Those who find standard cymbidiums too large and too dependent on low temperatures can enjoy the miniatures-hybrids between the big standards and several smaller species, notably C. pumilum. These more petite versions are easy to bring into flower, highly floriferous, and of a reasonable size (1 1/2 to 2 feet tall) for home decoration or the small greenhouse. The flowers are smaller than those of standards, yet profuse, and come in the same color range as that of the standards: white, pink, red, bronze, brown, yellow, and green, usually with contrasting lips. They tend to flower earlier than the standards as well: some will flower as early as July. Many miniature cymbidiums were bred to tolerate warmth and will often fail to flower when grown out-of-doors in the conditions that suit standard cymbidiums. They will thrive, however, when given the same conditions that suit cattleyas. It is always wise to check the growing requirements of a specific miniature before purchasing it.
- Cymbidium suave
- This Australian species grows mostly as an epiphyte on eucalyptus trees in Australia from the Tropic of Capricorn down to the Victorian border, a range of some 120 of latitude. It is a miniature plant, as cymbidiums go, with thin, stiff leaves about 20 in (50 cm) high and no pseudobulbs. In late spring the pendulous flower stems bear 3/4 in (2 cm) flowers in shades of green, some with a brushing of brown.
It is a charming species that should be more widely cultivated, though it seems to be somewhat more appreciated outside its native Australia. Needing good light and a quick-draining potting medium, it resents being disturbed and should be left in the same pot as long as possible. The ideal temperature required probably depends upon where, in its wide climate range, your particular plant came from. In general, this species will usually grow with other cymbidiums. Do not attempt to tear off the old dead leaf bases, as one would with other cymbidiums, as part of the living tissue is likely to be damaged.
Dwarf Cymbidium Species
These, the orchids of classical Chinese and Japanese art, have been treasured houseplants in Asia for 2,000 years.The plants are small with very tiny, sometimes subterranean, pseudobulbs and gracefully arching, grass-like foliage. The flower spikes are erect, and the small but characteristically orchid-shaped flowers are marvelously fragrant. Their popularity is now spreading from Asia to the worldwide orchid-growing community.
- Cymbidium ensifolium
- It might be easier to say where this wide-ranging species does not grow, as it appears in most countries where other cymbidiums are found. It is a largely terrestrial species of modest size bearing 12 fragrant 2 in (5 cm) flowers, green or greenish-brown in color, in late summer or fall. It has made its mark in hybridization by being a parent of the tetraploid Cym. Peter Pan ‘Greensleeves’. This orchid has, in turn, been responsible for extending the flowering season of modern hybrids by producing some attractive progeny which flower in mid – to late summer. Flowers from most of these hybrids do not last well when cut and are best admired on the plant.
Cym. sinense is a similar species, and both have been used to produce temperature-tolerant hybrids that will flower in the tropics. Most of this type of breeding is being pioneered in Florida.
- Cymbidium floribundum (C. pumilum)
- The 16-inch flower spike is crowded with 1 1/2-inch flowers of red or reddish brown. This spring-blooming orchid is an important parent of many miniature cymbidiums.
- Cymbidium goeringii (C. virescens, C. formosanum)
- In Asia this is called the spring orchid, because its short stems bear a single pale green or yellowish white flower in early spring.
- Cymbidium kanran
- Many fragrant little flowers, which range in color from green to red, decorate this winter bloomer. Some varieties have leaves striped with white.
- Cymbidium lancifolium
- The leaves are relatively wide (1 1/2 inches by 8 inches long). The foot-tall flower stalk carries up to six 2-inch flowers ranging from white to green with red veins and spots.
- Cymbidium sinense (C.fragrans, C. hoosai)
- This, the national flower of China, has highly fragrant, deep red, 2-inch flowers on a stem 2 1/2 feet tall. This orchid blooms in midwinter, just in time for the Chinese New Year.