Gardening – Easy care winter colour

One of the highlights of our winter garden are the cymbidium orchids, which start flowering in May and continue through to November. We have half a dozen or so varieties in terracotta pots and some lodged in trees scattered about the property. Both growing styles seem to flower equally as well, but the advantage of pots is that I can shift them to the deck in late autumn, so we can enjoy the flowers from our living area.

Cymbidiums are semi-epiphytic plants mostly from the Asian and northern Indian regions. Many of today’s large-flowered standard hybrids originate from high-altitude, cool-growing Himalayan and south-east Asian species. More recent hybridising has incorporated more tropical, smaller-flowered miniature species from Australia and Indonesia.

For gardeners in our region, cymbidiums grown in the right conditions are relatively resistant against pests and diseases, except for slugs and snails eating the flowers. As a result, I have never needed to spray my plants for anything, making them a welcome low maintenance addition to the garden.

Temperature is the most critical factor for cymbidium flowering, but fortunately our outdoor conditions of warm days and cool nights in late summer to autumn are well-suited to initiate flower spikes. Most cymbidiums can even stand light frosts and survive, although flowers may be affected.

Cymbidiums require the maximum amount of light possible, short of scorching the leaves, for good flowering. Healthy leaves are light green to almost lime-coloured, any darker may indicate over-feeding or lack of light. I usually place the pots where they get light dappled shade from overhead foliage during summer and shift to full sun in autumn and winter.

Cymbidiums need regular rain or watering during spring and summer when they produce all their vegetative growth, but they are more drought hardy than most garden plants. As semi-terrestrials they need free draining, slightly acidic soil conditions, so orchid potting mixes containing coarse coir or punga chips, pumice or bark chips are suitable. Cymbidiums are relatively heavy feeders compared to other orchids and are sensitive to nitrogen deficiency, which can reduce growth and flower spikes. I prefer to use slow-release fertilisers applied in spring, or just after division.

Cymbidiums are usually divided during summer. Division is carried out every three years or so, depending on the variety and pot size. Miniature hybrids often do well for five or six years before needing division and repotting. Plants are removed from their pots, old potting mix shaken off the roots and split, using a sharp knife or hand saw.

Cymbidiums develop from a small rhizome, this matures and swells into a false bulb, called a pseudobulb. Vegetative shoots (leads) arise from the base of this pseudobulb, as do flower spikes. After several years, the leaves break off and the bulb becomes what is known as a back bulb.

Back bulbs may be left on the division to add strength or removed to propagate. Divisions should have three to five green pseudobulbs with leaves as a minimum to bloom satisfactorily next season. Place the back bulb against the side of the pot and the active growing pseudobulb (the lead) of the division farthest from the side of the pot.