Cymbidium Orchids
CYMBIDIUM (Abbreviation - Cym.)
There are approximately 50 species native to tropical Asia and Australia.
Most are terrestrial, but some are epiphytes.
Cymbidiums produce pseudobulbs, which can be large or in some cases very small; even insignificant. Each pseudobulb of a healthy plant will have many leaves under good conditions.
These leaves are normally long narrow and thick, but can sometimes vary.
The plants grow continuously, without a quiescent period that is typical of other orchids.
Appearing on lateral racemes, the flowers of this plant have petals and sepals that are similar and a lip that varies from entire to 3 lobed.
The Cymbidium genus is a very diverse group, with an immense number of hybrids and varieties.
Some Cymbidiums are more cold tolerant than Cattleyas, withstanding temperatures to around 7 degrees celsius.
In the cooler southern regions of Australia, such as Melbourne and Adelaide, many people have outstanding success with Cymbidiums grown in a shade house, on a verandah or under the protection of a large tree.
Culture
Watering is ceased over winter, and in wet areas, some people turn pots on their side for a period to stop the roots getting too wet and rotting. Watering in the evening in summer helps drop the root temperature for the night, which in turn helps initiate flowering. In very hot late summer conditions, apply a weak epsom salts solution to Cymbidiums weekly. Feed Cymbidiums regularly over spring and autumn, but not through late summer, as being short on nutrients in January/February, helps promote flowering. Potting media needs to be well drained, preferable a mix specifically made for Cymbidiums.
Flower spikes develop over winter and bloom throughout the spring. Frost during these times will bleach and distort flowers, and can even kill the plant. The plant prefers winter minimums to 10oC and summer maximums of 24-27oC, but will tolerate a much wider range of temperatures. Many of the modern hybrids prefer temperatures around 20‑27 degrees celsius over summer. Cymbidiums will perform better if winter temperatures can be kept around 10 degrees celsius and those in colder climates should consider bringing them indoors over winter. In hot summer districts, light shading (to 30%) may be required to cool the plants, or light watering or misting.
All Cymbidiums prefer indirect sunlight, particularly once flowers open. However, some are more sun tolerant than others. Cymbidiums tend to tolerate the most direct sunlight of all orchids, especially in the growing phase before flowering commences. Pink or red flowering Cymbidiums tolerate brighter light than green flowering types. Yellow and white flowering varieties vary in their light tolerance. Yellow or green varieties produce more vibrant flowers if greater shade is provided. Return to better light conditions after flowering.
Flowering is thought to be initiated by long bright days combined with cool nights. Flower initiation occurs in mid to late summer in all Cymbidium species, but actual flowering time will depend on cultivar. Maximum flowering is achieved when day temperature is 21 degrees Celsius and night is 14 degrees over summer. Flowers are long lasting. A spike can last easily 6 weeks.
Every variety of Cymbidium needs to reach a certain size before it will flower. This varies from one variety to the next. For one it may require three mature bulbs, and for another three times that number. Plants can be grown from back bulbs (pseudo bulbs), similar to the way Cattleyas are propagated, however with Cymbidiums, one pseudobulb is sufficient for a new plant. When dividing, dust any cuts with fungicide (eg. sulphur) to minimise chance of rot.
Bulb rot is common if pots get over-wet in summer. Control with a Fongarid drench. Black leaf spot often occurs and can be controlled with a mancozeb spray. If the summer is dry, bulb rot is unlikely,
but mites are more likely. Other pest and disease problems include:
Mealy bugs - cluster around the pseudobulbs: use systemic insecticide (eg. Omethoate or Confidor.
Scale - located at lower sections of the plant : use systemic insecticide.
Red spider mites - cause silvering of leaves, delicate webbing and, a more minor symptom of misshapen leaves: use a miticide, discard infected plants or introduce biological control agents.
Aphids - these insects such the sap form health new shoots and flowers: Control by pyrethrum or a range of other insecticides.
Leaf spots - commonly caused by caused by fungal diseases, control by removing infected leaves or in extreme cases by spraying with a fungicide (eg. mancozeb). Some streaks & spots may be caused by virus. Virus infected plants are best isolated, or even destroyed.
Leaf tip browning - caused by water stress and high fertiliser content: improve cultural practices
Cymbidium Mosaic Virus - mild infections may be similar to leaf spots, as it develops it causes distortion and more discolouration: dispose of infected plants.
Some growers separate cymbidiums into two groups: those from warm zones and those from temperate-cold zones.
Cultivars
TYPES
Some species cymbidiums are grown, however most cultivated cymbidiums are either "standard" hybrids or miniatures.
There are many regular hybrids that can reach a height of more than 1.5 metres, with a single spike carrying as many as 30 flowers. Miniatures are smaller plants with lower foliage and smaller flowers.
Miniatures generally like to be watered all year round, while the larger hybrids often like to have a period of dryness. Miniatures also tend to be more resilient in hotter temperatures.
Species
There are more than 50 recorded species
C. canaliculatum is a dense plant with two to six thick deeply channelled leaves per pseudostem. It has fragrant flowers vary from pale green to reddish-black and appear in racemes of five or up to sixty.
C. eburneum has diminished or insignificant pseudobulbs, leaves to 60 cm (24 inches) long and an upright flower stem carrying only one to three flowers. The flowers are fragrant and mainly ivory white. The lip is white with a yellow centre. There are named varieties in which the flowers vary both in colour and shape.
C. elegans produces thick pseudobulbs, narrow leaves to 70 cm (28 inches) long, and a dense spike of 4 cm (1.6 inches) diameter flowers, commonly brownish yellow with red dots on the lip.
C. giganteum has arching linear leaves to 70 cm (28 inches) long, and ovoid pseudobulbs. Flower spikes carry up to 15 flowers, each to 10cm across, commonly green to brownish-yellow and fragrant.
C. grandiflorum has leaves to 70 cm (28 inches) long and flower stems to 1 metre long. The flowers are fragrant, up to 10 cm (4 inches) across and variable in colour; often greenish or yellowish with darker markings.
C. insigne has been grown extensively as a species, and as a parent for hybridisation with other species. It has spherical pseudobulbs, leaves 50 cm (20 inches) to 1 metre (3.3 feet) or longer. Up to 15 flowers, each to 10 cm (4 inches) across, can occur on each flowering spike. Flower colour is variable but often pale rose to lilac flowers with a darker lip in the centre. C. insigne Album has a white lip with green markings.
C. Lowianum grows 60 to 90 cm (2 to 3 feet) tall. Each flower spike can carry up to 25 flowers, 10cm in diameter flowers. A number of cultivars exist, and flower colour can be variable; however flowers are commonly fragrant, greenish with brown veins, and a yellow and red marked central lip.
C. madidum is a large clumped plant with thin dark green leaves. Racemes (flower stems) can reach 60 cm (2 feet) long and carry 70 fragrant flowers. Flower colour varies from pale to brown-green.
C. pumilum is a dwarf species which has been used to produce some miniature Cymbidiums. Its leaves reach 30 cm (1 foot), and flowers up to 3 cm (1.2 cm) across occur on a dense spike. Flowers are commonly white to pinkish with reddish markings, but there are variations, including C. pumilum 'Shuo-Lan' which has green to brown sepals and a yellow lip with red markings.
C. sauva produces long grass-like leaves with fragrant brownish green flowers borne on 30cm long racemes.
C. zygopetalum produces vibrant pink-purple and brown petals flower parts.
Cymbidium Hybrids
There are countless hybrids of Cymbidium grown throughout the world, and new ones being released constantly. It is largely pointless to refer in any detail to specific hybrids, given that the choice is so diverse. The following are however just some of the older hybrids which are often referred to in literature.
C. X Alexanderi is a hybrid of C. Veitchii and C. insigne. Flowers reach 10 cm (4 inches) across and may be white, cream or bluish pink. This hybrid has been used extensively for breeding other cultivars.
C. X Veitchii is a hybrid of C. eburneum and C. Lowianum, and it has large fragrant flowers to 12cm across.
CYPRIPEDIUM
(Abbreviation - Cyp.)
There are thirty to fifty species in this genus, which is related closely to Paphiodedilum & Phragmipedium. Classification has often been confused between this and other genera (eg. Selenipedium has often been included in this genus).
Cypripediums are known to occur from sub-arctic to subtropical areas in northern hemisphere Most are north of latitude 35o north.
These terrestrial plants are deciduous, with the foliage dying back to the rhizome in winter. They commonly grow in woodland or meadows and typically have a long leafy stem rather than a fan of basal leaves growing from a rhizome. The lower stem is hairless. Height can vary a great deal, from 10 cm or 4 inches (in full flower) to 1.5 metres (5 feet) tall. Cypripedium flower in spring or summer. The flowers are white with pinkish to purplish mottled colourings on pouch. The lip of the flower extends to form a sac or pouch.
Culture
Many grow well in the open ground in temperate climates. Most prefer well drained, high organic soil
and must be protected from bad frost or snow.
Species which occur naturally in snow prone areas become dormant over winter, and the roots are covered with snow. In such situations, growth should not begin until all snow has gone. A flush of growth followed by a late fall of snow can be fatal. Otherwise most Cypripedium are hardy.
Rhizomes often branch allowing propagation by division.
Cultivars
C. acaule (Pink Lady's slipper) has solitary flowers, reddish purple with a pinkish lip. It is extremely hardy in cooler climates, (growing well in Britain), and needs acidic soil.
C. Calceolus has foliage up to 70 cm (28 inches) tall. The shape and colour of flowers can be variable (yellow green to purplish or brownish are common). It is perhaps the most commonly grown species with many different named cultivars grown. Varieties occur naturally from Texas to the Yukon in the north of Canada.
C. Calceolus pubescens (Yellow Lady's Slipper) produces solitary green yellow flowers, with yellow lip/pouch.
C. candidum grows to 30 cm (12 inches) tall, and produces solitary flowers on a stem, sepals and petals are greenish with dark markings and the lip is white with purple spots.
C. macranthum produces solitary blooms, dorsal sepal, petals and lip are pink to purple, lateral sepals greenish-brown.
C. reginae is particularly hardy, but is covered with hairs which can irritate the skin. It used in hybridisation with Phragmipedium. Growing to around 80 cm (32 inches) tall, the petals and sepals are white, and the lip is white with purplish or reddish markings.
Some hybrids are grown including C X Andrewsii which is produced from C. Calceolus parvifolium X C. candidum.
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