How to grow cymbidium orchids
Cymbidiums are bold, colourful orchids for a bright room, producing spires of exotic blooms from late autumn to spring. They like slightly cooler conditions than many other houseplants, and bloom best after a few months outside in summer.
- Tender flowering houseplant
- Exotic blooms from late autumn to spring
- Like bright light, but shade from strong sun
- Keep at 10–24°C (50–75°F)
- Move outdoors in summer, to stimulate flowering
- Grow in bark-based orchid compost
All you need to know
What are cymbidiums?
These tender orchids flower from late autumn to spring, at a time of year when few other houseplants are in bloom. They produce arching stems that carry lots of large exotic flowers that are often speckled or streaked. There are lots of species and cultivars to choose from, with flowers of various colours. The flower stems sprout from a fountain of long, thin, evergreen leaves.
Cymbidiums are available in two sizes:
Standard – up to 1.2m (4ft) tall and ideal as a spectacular centrepiece for a bright room
Miniature – 30–60cm (1–2ft) tall and easy to accommodate on a windowsill
There are many different flower colours to choose from, including pink, purple, ruby, yellow, lime-green, cream, white and more. The petals are often splashed or speckled with contrasting hues.
New hybrids are introduced every year, but most are sold unnamed. It is usually only specialist orchid nurseries that offer named species and hybrids. The newer introductions tend to be easier to grow.
Several cymbidiums have an RHS Award of Garden Merit, which means they performed well in RHS trials, so should do well in your home:
Cymbidium erythraeum – fragrant green flowers with red speckles
Cymbidium lowianum – green flowers on stems up to 90cm (3ft) tall
For more ideas and inspiration, visit the Glasshouse at RHS Garden Wisley to see all kinds of orchids in full bloom. Many of the RHS Shows also feature spectacular displays by orchid nurseries, and every spring the RHS holds an orchid show.
Cymbidiums are available from many houseplant retailers, including garden centres, florists and some supermarkets. They are also available from online plant suppliers and tropical nurseries. For the widest choice, go to specialist orchid nurseries.
Buying: garden centre plants
Buying: mail order plants
How to choose healthy plants
Cymbidiums can be kept in their original pot for the first couple of years. They should then be repotted at least every two years, as bark-based orchid compost deteriorates over time. Vigorous plants may need to be repotted sooner if they are very cramped in their pot. The best time to repot cymbidiums is in spring, just after flowering but before new growth starts.
Choose a container that has enough room for two years’ growth (about 10cm/4in wider than the previous one). Avoid using a much larger pot (overpotting), as the compost will stay wet for longer, which can cause root rot. Transparent containers are not necessary, although they do allow you to see if the compost is still moist below the surface, which can help you avoid overwatering. You will also need a bark-based orchid compost.
Repotting is very straightforward:
Carefully tip the plant out of its container. If it has made a large clump of ‘pseudobulbs’ (swellings at the base), divide into several new plants by sawing through the centre of the clump and the rootball with an old bread knife. Aim for at least five pseudobulbs on each new plant
A large cymidium can be divided into several new plants
Remove all the old bits of bark compost from the rootball, gently untangling the roots if necessary
Snip off any dead or rotten roots (these may be brown, mushy, shrivelled or hollow), then shorten the remaining healthy roots (these should be white and firm) to 15–20cm (6–8in) long
- Hold the plant in the new container at the level it was previously growing, and fill in the spaces around the roots with fresh bark-based orchid compost. Gently firm it in as you go, especially around the edges. If done correctly, when you pick up the plant by its stem, the container and compost should come with it and not fall away. Loose compost will cause the plant to be unstable and may damage the new root tips, stopping them from growing
Repot your cymbidium at the same level it was previously growing
- Finally, give the plant a thorough watering, ensuring the entire rootball is moistened. Let the water drain straight out – and don’t leave the plant sitting in water
Check out our guides to repotting houseplants:
Cymbidiums need good light all year round, especially in winter. But keep them out of strong summer sun.
Cymbidiums prefer cooler conditions than some other tender indoor orchids, ideally 10–24°C (50–75°F). Keep them below 30°C (86°F) in summer, and at 10–14°C (50–57°F) in winter.
It’s best to move cymbidiums outdoors from mid- to late summer (typically June until mid-September) to a warm, sheltered spot in light shade. Gradually acclimatise them first, by hardening off, to prevent leaf scorch from cooler temperatures or stronger sun. This spell outdoors, with a clear difference between day and night temperatures, helps to stimulate the formation of flower buds.
See our tips on moving houseplants outdoors for the summer.
Water cymbidiums regularly and moderately in spring and summer. Let the compost dry out a little before the next watering. Reduce watering to weekly or fortnightly in winter.
Use rainwater or filtered water whenever possible, especially in hard water areas. Water from above, making sure excess water can drain out straight away. Don’t leave plants sitting in water, as this can lead to root rot.
In spring – apply a half-strength general liquid fertiliser or orchid fertiliser for three waterings, then use only water the fourth time to ensure any potentially harmful accumulations of salts are washed out
In summer and autumn – switch to a high-potassium specialist orchid fertiliser, to stimulate flowering, for three out of every four waterings (using just water the fourth time)
- In winter – stop feeding altogether or feed only occasionally with a half-strength general-purpose liquid fertiliser or orchid fertiliser
Flower stems start to grow in mid- to late summer, when plants need good light and a distinct drop between day and night temperatures. This is best achieved by moving plants outdoors, into a sheltered spot, out of direct sun
Support developing flower stems with bamboo canes, as they can become top-heavy in flower. Insert the canes into the centre of the clump, so you don’t damage new roots near the outside
To prevent bud drop, keep plants below 15°C (59°F) while the flower stems develop. Wait until the flowers have opened before moving plants into a warmer position, to put on display
Each stem generally flowers for six to eight weeks. Ideally keep plants at about 21°C (70°F) during flowering. At higher temperatures the blooms may fade prematurely
- Cut stems down to the base after flowering
In mid- to late summer, ensure cymbidiums have good light and a distinct drop in temperature at night, to help initiate flowering
Cymbidiums need very little pruning – simply cut back the flower stems to the base once all the blooms have faded.
It’s easy to make new cymbidium plants by dividing a mature clump when repotting in spring, especially if it has become overly large or if some of the pseudobulbs (swellings at the base) have died and turned brown.
Remove the plant from its pot, then cut it into several pieces by sawing through the centre of the clump and the rootball with an old bread knife. Each piece must have at least five healthy pseudobulbs. Discard older or shrivelled material. Pot up the new smaller plants individually into bark-based orchid compost. They will usually take two to three years to flower.
Divide large cymbidium clumps in spring
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