Dendrobium

This morning, as I was watering the orchids, I came upon one of those serendipitous surprises that all orchid growers will experience now and then: our Dendrobium crumenatum has started to bloom again! Any of you who know this plant will understand my feeling.

I had received this orchid by accident. When Dough deMoss was packing up some of Mr. Warne’s Cattleyas for me (in Honolulu), this small seedling was found growing in one of the pots and both gentlemen very kindly agreed to let me keep it – free of charge. I did not know the plant and even after reading about it (learning that in grew in very many tropical places, mostly in S. E. Asia), I did not think it was very wonderful. It grew and grew and grew, like a large green Daddy-Long-Legs, sprawling all over the other hanging baskets. I wondered if it would ever bloom! Then, one day (just like today), there were dozens of snow white bells hanging from the skinny canes, fragile and fragrant, sparkling like silver in the sunlight. I was enchanted. Two days later, the show was over. But the flowers appeared again and again throughout the summer, like magic. Someone said they are called “Rain Orchids” and “Thunder Orchids”.

These names will give you an idea as to their blooming: it has to do with the weather, or rather temperatures. What you need is a plant that has at least one mature stem with a bare, skinny end and keep it warm, sunny, well watered and fertilized. Then about 10 days before you want flowers, you spray it with very cold water and sit back and watch – cold showers do strange things. I have taken cuttings to give away or sell and while these little guys were sitting on the bench in the greenhouse, they all flowered at the same time as the large mother plant. With a little tongue-in-cheek I gave them the clonal name ‘Honolulu Snow’.

This is one of the many surprises that can come your way when you grow Dendrobiums. There are so many different species (about 1,000) growing in a very large area from India through South Asia to Korea, Japan and further south through the Pacific islands, New Guinea, New Zealand, along the East coast of Australia including Tasmania. All these different species will of course be used to different conditions. It can be frustrating to ask some expert: How can I grow a Dendrobium? The answer is the same as to the oh-so-common query: How often do I water my orchid? It always starts with: It depends; and that answer is not very satisfactory to someone who is seeking help.

What can be done? We can suggest to people to read up on their plant and find out from where it comes. They can look things up on the Internet. We suggest that they join orchid societies. They could go and visit orchid greenhouses and nurseries. We can try to explain that to grow and flower successfully, each plant will need to have its home environment copied. If this means that one has to create a monsoon climate in order to flower, for instance, a Den. aggregatum – then perhaps this species should be grown in a greenhouse. The plant comes from an area of relatively dry winters with an average summer rainfall of over a meter. Maybe the plant comes from the highlands of New Guinea, like Den. cuthbertsonii. Then, if you want to make this little plant happy, you have to create an equatorial cloud forest.

Of course it all depends – not only on the plant and its requirements but also on the grower. Are you willing to provide the correct environment for a particular species? If you have somehow managed that, then one morning you will be tending your plants and be surprised by the cool, sweet perfume of Den. crumenatum ‘Honolulu Snow’.

Ingrid Schmidt-Ostrander - Canadian Orchid Congress