Cymbidium canaliculatum.

[Gary S]

This is the 3rd article on our Aussie Cym’s – the flamboyant Cym canaliculatum. This one sits in the middle of the other 2 Aussie cyms with regards ease of cultivation, see if you can pick the 2 main differences it needs.

In situ in the bush

Pseudobulbs can be up to 120mm long and 40mm wide. Leaves are erect, thick and fleshy deeply channelled and there is a reason for this, which I will come to later. They can be up to 500mm long and 40mm wide with up to 6 leaves per bulb. The raceme can extend to over 400mm long and carry up to 60 flowers or more. Flowers are 35mm x 30mm on average and come in a large colour range from the dark maroon of the var Sparkesii , through greens , browns ,yellows and whites and all colour combinations some with heavy splotches and markings. There are clear colours without markings and alba clones in existence – more info on alba types to come in the future hopefully. Flowers are fragrant but not as much as madidum and suave. It flowers from September to November. There are colour forms in cultivation that the average grower has not seen, they are held under close wraps for various reasons, I will try and get some pics, but no promises though.

It is the most widely distributed of our Native Cym trio, from the Kimberley region of north WA across northern Australia down into QLD and its southern limit is the Hunter River in central NSW. It will grow from the coast at sea level in northern Australia up over the ranges at altitudes to 900metres and into inland western plains in quite arid zones. It normally only grows in drier forest and open woodlands, you will not see it in the rainforest.

It has a very extensive root system with roots penetrating for metres deep into the fissured bark of its host tree and heartwood of decaying stumps. The roots are quite thick to help in finding every available water source in the drier months.

This orchid in situ is quite common in a wide range of its habitat area and is able to withstand drought conditions for years at a time. I have seen it growing on fence posts surrounding farms in open agricultural areas – so the seed will travel long distances on the breeze when released from the pod. Clumps in nature can be quite large and grow quite close to the ground as the host trees in the arid areas are not tall at all. This orchid in the wild can withstand temps between minus 12 deg C to over 50 deg C. Even in drought conditions the root system hardly ever becomes dry, buried deeply in the heartwood of the tree, as the channel like leaves direct any moisture provided by rain, dew, frost and mist to the base of the plant to eventually make its way to the root zone. Decayed leaf matter provides the main source of nutrients to the plant in nature.

At home in the greenhouse.

This orchid is easier to establish and grow from flask through seedling size into larger plants than Cym suave, providing you maintain the following requirements. In winter (May through to August or when the raceme is half developed on a mature plant) hang the orchid up high in the greenhouse under solid rain proof cover and do NOT water it at all during these months. Once mid Spring is here then start watering the plants and they will take all the water you can give them over summer. Tank water supplied by rain is far better for canaliculatum than town water – but this probably applies to all orchids really. The aim with Cym canaliculatum is to exactly replicate how it grows in its natural habitat – that is a dry winter and wet summer!

This species has become more available in flask over the last few years using a lot more forms than the usual Sparkesii that was only available in time gone by and all combinations of them. I would try and make certain that the flask comes from a seller that you know and trust, again taking it out of flask, be prepared to lose a certain percentage of plantlets – use the premium NZ sphagnum moss and be careful with the watering, also they are slow to grow and establish. Grown on seedlings are available, but you will need to hunt them down and more mature plants that are established already are also available from time to time – but they will be expensive usually. You should never see this species for sale bare root as it grows in areas where the host tree is not logged at all- so a bare root specimen will be illegally collected and like Cym suave it has an extensive root system that will be hacked to pieces with most remaining buried deep in the host tree.

Research.

Again research done by a well known local orchid grower has found the following conditions are also necessary – and he grows this species to perfection!
It will grow just as well on a live host or dead stump or even a fence post provided the roots have a long cool root run and can penetrate deeply – hence the need for a suitably shaped deep container. The compost pH at the base of the plant was found to be 6.6 to 7.5 over a wide range in its habitat, whereas the heartwood pH level at the rootzone was between 9 to 9.5. Therefore Cym canaliculatum likes very alkaline conditions – totally the opposite to Cym suave.

It is recommended that this species receives a spray of lime at 1 gram per litre of water 4 times a year. It grows vigorously in Spring and Summer and benefits from fertiliser applications at this time of the year – I use half strength- together with the sprays of lime to maintain and adjust the pH level of the mix.
I find this orchid likes a good deep pot, not your usual standard or squat pot that most orchids would be happy in, better still long terracotta pipes (1000mm) if you can find them or hollow tree stumps or limbs from hardwood trees (gums). Keep the roots cool, the mix at the correct pH and NO water over winter at all.

As you can see from the 3 article’s the 3 Aussie Cym’s are quite diverse in their range and all 3 have very differing requirements (although madidum is the easiest and more forgiving), really the only sort of commonality is the size of the flowers amongst the 3 species – being rather small compared to some of the South East Asian Cym species. I hope these posts have provided food for thought for the members. Maybe the information on pH levels required by suave and canaliculatum will be valuable to the hybridisers and commercial growers who are using these species in their programs.

Gary..