Cymbidium orchids

Cymbidiums are the most popular orchids grown in Australian gardens. Most are grown in containers, but these exotic and glamorous plants can also be grown in garden beds in warm, frost-free climates.

These orchids form clumps of light green strappy leaves. In winter and early spring, they produce robust stems of flowers with many flowers on a single stem. These orchids are ideal for beginner orchid growers. Their flowers are large with colours that include green, pink, magenta, yellow, cream, white and brown tones. Often blooms have distinctively marked patterns on the labellum (lip).

Growing conditions

Aspect Cymbidiums need a lightly shaded position out of direct sunlight, which may scald foliage and flowers. Avoid full shade as, although the plants will grow, they will not flower. Ideal positions include a fernery, balcony, or dappled light under a tree. They are not suited to indoors unless in a conservatory but can be brought indoors for up to six weeks while in flower.

Soil Cymbidiums don’t grow in soil. In their natural habitats they grow in leaf litter so select a coarse growing media made up of un-composted bark such as a purpose-made orchid potting mix, which provide excellent drainage. Select pots with lots of drainage holes and elevate pots slightly to aid drainage. As these orchids have large, white fleshy roots they can rot quickly if the plants are allowed to sit in water or very wet potting mix.

Climate Cymbidiums come from the tropics, subtropics and some warm temperate zones including parts of Australia, often from high altitudes. They do well outdoors in warm temperate to tropical conditions but need protection from cold and frost in cold zones.

Red Orchids image

General care

Watering Water cymbidiums regularly and mist the leaves to keep them cool on hot summer days. In warm weather, cymbidiums should be watered several times a week but always allow water to drain freely. Watering is also vital when the plants are flowering but avoid wetting the blooms.

Feeding For good flowering, apply fertiliser from spring through summer and again in autumn. Specially formulated slow-release fertilisers are available for cymbidiums such as PowerFeed Controlled Release for Flowers, Fruit & Citrus. Plants can also be liquid fed with PowerFeed All Purpose including Natives or PowerFeed PRO SERIES Roses & Flowers. Orchid specialist, recommend a liquid foliar feed every 1 to 2 weeks at a reduced rate of 20mL of concentrate per 9 litres of water (standard watering can).

Pruning and dividing Remove spent flower stalks in spring and regularly remove yellow or dead leaves. Repot cymbidiums every three years or when the plant has outgrown its container. The best time to repot is after flowering in mid to late spring.

When repotting, identify the three growth stages within the clump. These are the old, brown leafless bulbs known as back bulbs, old but leafy bulbs that are no longer flowering and young bulbs that should flower in the next season. Divide overgrown plants into two or three smaller sections. Remove back bulbs but leave older, leafy bulbs as they fuel growth by providing nutrients that encourages the growth and flowering in new bulbs. Mix Seasol Plant + Soil Booster into the new growing media and water in with Seasol.

Watch for Orchids can suffer from pest and disease problems but plants that are well cared for and receiving ideal light levels are usually trouble free. Watch out for slugs and snails, two-spotted mite, mealy bug, scale, and orchid beetle. Search and remove snails and slugs from within the clump and under the pot. Snails can also be removed by hand. Also search for and remove orchid beetles, which are small orange and black insects. Other pests can usually be controlled with EarthCare Enviro Pest Oil insect spray. Apply to both sides of the foliage and repeat 14 days later if needed.

The main disease problems are root rots caused by poor drainage and overwatering. Mottled leaf spots and other damage is often caused by viruses such as cymbidium mosaic virus, which also affects growth. As there is no cure for virus disease, badly affected plants should be destroyed.