Dendrobium heterocarpum – A Spotlight on the Species

This is a very underestimated species and one that is worthy of a place in every Dendrobium collection. It’s a cool species, found in the Himalayan regions of India and China, down into the warm tropical valleys of Sikkim and Assam, through the foothills of Khasi. It is also widespread throughout Indo-China, Sri Lanka through Malesia and into the Philippines. As can be expected with a species that is as widespread as this, it is adaptable to many temperatures and conditions. It is as much at home in the warm tropical house as the cool house. I always grow it with my cooler Dendrobiums and find it is normally the first Dendrobium species to flower. Usually starting to produce it’s buds as early to late October, with the flowers opening mid-December to mid-January. I leave it in my cool house right through the growing season, giving it heavy shade, high humidity and strong air movement. It is fed weekly and the root system is thoroughly soaked as soon as it dries out, aiming to get as long a cane as possible before the growing season ends. I mount them as they tend to become more and more pendant as the canes get bigger and it is easier to grow rather than continually fighting to keep the canes upright in a pot.

As the temperature drops in late summer/early autumn I stop feeding and remove the plant from the shade and allow as much bright light as possible to ripen the canes and initiate flower buds. By mid to late October the temperature is usually dropping, in the cool house, to around 5c – 8c depending on the weather, and the plant starts to drop it’s leaves. I try and keep the temperature to 5c at the lowest. By the beginning of November you can see the buds begin to push through from the leafless nodes of the canes, they come from each node nearly along the full length of the cane. Between one and three buds appear at each node, usually two though, and they begin developing relatively quickly. In late-November I move the plant into a warmer house where night temperatures are kept to a minimum of 10c and allow the plant to flower at these temperatures. The flowering period can be later if plants are left in cooler conditions in the autumn/early winter. I prefer to increase the temperature for early flowering so I can get a good long growing season for maximum size of canes.

The flowers are pale buff to creamy-green in colour and lip is similarly coloured with golden brown stripes in the throat, the lip is covered in golden brown hairs and reflexes at the tip. In the majority of cases the flowers are scented like Raspberry, although occasionally they aren’t. The flowers last between 15 and 20 days and a week or two after going over the new growth begins.

 

Dendrobium heterocarpum has been used in several registered hybrids, especially during the 19th century. However, it appears to have been registered some 12 times in crosses with Dendrobium nobile, with as many different registered names for the same cross. This is apparently down to the species having been known under numerous names, for example, Dendrobium aureum. Also, in these early days, reverse crossings had also been registered with a different name. I am assured that the correct name for this cross is Dendrobium Ainsworthii* first registered by Dr. Ainsworth in 1874. Having browsed through it’s use in hybrids over the years I think it still has much potential as a parent if we were to discount the numerous registrations with the same cross. I’m sure, according to my own experiences with this species, that it may be a useful parent for adding vigour and ease of flowering to it’s progeny and possibly early flowering.

We have Dendrobium heterocarpum, in limited numbers, for sale in our online shop.

* I am grateful, as always, to Julian Shaw, the Orchid Registrar at Kew for his endless patience answering my queries.

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