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Growing Cymbidiums, the easy orchid

Many varieties of cymbidium are available. Each individual butterfly like bloom is ideal for a buttonhole or corsage.

Many varieties of cymbidium are available. Each individual butterfly like bloom is ideal for a buttonhole or corsage.

Many of the visitors to this website have probably been given a cymbidium orchid in a pot and had no idea how to care for the plant. Orchids have an aura of mystique, but they are really simple to look after, if you follow some basic rules.

In this post we will try and give you an insight into the cymbidium, the most popu­lar orchid for a gift, together with tips on how to grow them successfully in the home environment. Orchids are certainly different from any other form of plant life, but once one understands their structure and needs, they are not difficult to grow.

Orchid flowers are classed as resupinate — that is upside down, with the pedicel or ovary turned through 180o. The cymbidiums usually have five petals surrounding a central trumpet‑shaped lip. They are not as frilly as the Cattleyas and the petals are thicker and not as delicate in appearance.

Cymbidium is the oldest cultivated orchid, and there is evidence that they were grown in China 2500 years ago in records from 500 BC at the time of Confucius.

The genus consists of about 50 species and, from these, thousands of hybrids have been bred. 

The wild types are found growing naturally in China, and Japan through the Himalayas, South East Asia to Australia.

They may be terrestrial in habit or epiphytic or even lithophytic (growing on rocks).

WHAT TO DO IF YOU ARE GIVEN A CYMBIDIUM ORCHID AS A PRESENT

Orchids are becoming popular as potplants, and not all orchids have to be grown in a greenhouse. If you can grow African violets successfully, then orchid growing is relaively easy. Here we will discuss the growing of cymbidiums, which are the most likely variety to be given as gifts.

Cymbidiums come in a vast range of flower shapes, colours and sizes. The plants are characterised by their long flower spikes, often a metre or more, which can have up to 25 or 30 flowers, depending on the variety. The flowers are long‑lasting and may last for as long as 10 to 12 weeks on the plant.

Cymbidiums are not difficult to grow provided a few of their cultural requirements are understood. For a cymbidium to flower successfully it requires as much light as possible in the summer, and a night temperature drop of between 5 and 10oC, which generally ensures a successful flower spike set.

The miniature cymbidiums are less dependant on the diurnal temperature range, as their ancestors originated in tropical conditions. By and large cymbidiums can withstand a wide range of temperatures, although it is not advisable to grow them unprotected in areas which receive heavy frosts. The large flowering cymbidiums do not do well in hot tropical areas.

LIGHT REQUIREMENTS

Poor light is often the most common reason why an orchid fails to bloom. Remember cymbidiums are vigorous growers and require as much light as possible in the summer and autumn. The optimum is to shade your plants with 30 to 40 percent shade cloth. Where this is not possible, place your plants on an east facing wall, which will allow them to get full summer sun until about 11 a.m. every day.

The quickest way to assess whether your plants are receiving the correct light is by the colour of’ the leaves, which should be yellow green. Very dark green leaves indicate a plant that has been heavily shaded and in most cases will not produce a flower spike.

WATER REQUIREMENTS

During the summer cymbidiums require a large amount of water. If one’s potting mix is very porous and the day temperatures are high, daily watering will probably be necessary. During the cooler months watering every three to five days is sufficient.

FEEDING

As already stated cymbidiums are vigorous growers and therefore require a constant supply of nutrients. During the main spring and summer growing period feed your plants a high nitrogen feed, such as 3:1:1 or 5:1:5 slow release bi‑annually, with a little phosphate supplement in the winter.

Remember not to over‑fertilise your plants, because the resultant salt buildup causes leaf and root damage. An over‑fertilised plant shows tip burn. This problem can easily be overcome — either repot the plant or flush the soil thoroughly with water to remove excess salts.

If you are a lazy gardener the plant fertiliser spikes are also satisfactory. A bi-annual application would suffice.

POTTING MIX

Most specialist growers have their own mix, but you will find that medium grade local pine bark (40 percent by mass), 30 percent coarse riversand, 30 percent neutral peat with a cup of superphosphate per cubic metre will work well.

GROWTH HABITS

Cymbidiums are evergreen with long leaves and a base of thick bulb‑like swellings called pseudobulbs, which act as storage organs for food and water. Most plants start their new growth cycle in late winter or early spring. A new growth or growths emerge from the base of the pseudobulbs.

Flower spikes are produced during the summer at the base of the new growth.

REPOTTING AND PROPAGATION

Repotting is best done in early summer when root growth activity is increasing. The plant should be removed from the pot and all the old potting mix washed off. Then break the plant into three and four bulb divisions and cut away the old and broken roots with flame‑sterilised secateurs.

Select a new container which will allow the plants at least two years growth. Hold the plant two to three centimetres below the rim of the pot and add the mix, shaking the pot at intervals to ensure the mix fills all the gaps between the roots. Then water the plant well and keep in the shade for a week. The repotted plant should flower in the following season.

Where possible remove the backbulbs and strip them of their leaf fragments and roots. Place the bulbs in 7,5cm pots, in a warm location. New growth should occur within six weeks. These new plants will flower within two to three years.

STAKING

Staking is very important as it ensures the flowers are presented correctly. The flower spikes are also long and heavy and therefore require staking. Usually a heavy gauge wire cut into metre lengths is adequate. Tie your plant to the stake at intervals.

PESTS AND DISEASES

Aphids are a common pest found on the flower spikes. Spray them with Baysol or any appropriate organic insecticide. Red spider mite are the most serious pest of cymbidiums. As most are resistant to the commonly sold miticides, try to maintain a relatively high humidity around the plants, which helps keep them in check.