NEWS
Our meeting on 30-April coincided with the 70th birthday of Bill Gardiner, our Chair, so we sang ‘Happy Birthday’ to him and were treated to delicious cake with our tea and coffee.
We were delighted to welcome six newcomers to the meeting – as with any Society, we need regular infusions of ‘new blood’ to keep the Society fresh and interesting.
The winners’ show table was won by Andy Gissing with his splendid example of Dendrobium cuthbertsonii ‘Swiss Winter Palace’. Phil Broom’s Cymbidium ‘Sea Gem’ took the novices top spot.
GUEST SPEAKER
Our guest speaker was Huw Richards from Cambridge Orchid Society, who gave a talk entitled ‘Dendrobiums and their relatives’. He said some of their members struggle with many of the speakers because their talks tend to be rather technical. So he thought ‘Why don’t I do lots of research and see whether I can come up with a talk?’. He chose Dendrobiums as his topic as they are one of the largest groups and are very popular orchids, and he likes them! He reckons he must have done something right as clubs ask him to return!
So, the result was a detailed and informative talk on the distribution and habitats of Dendrobiums. Species can be found growing at sea level, in hot and often dry conditions, right up to high elevations where conditions are relatively cool. They grow naturally in a very large area covering west India and as far as Korea and Japan. There are approximately 1000 types and vary from needing low to high temperatures, wet and dry conditions (most wet, dry, wet, dry), small to much larger flowers, some only lasting a day and some weeks, also small as well as large plants; most have very thin roots but there are a few that have thick roots similar to Vandas.
With many of his own plants on hand for illustration, he guided us through some of the various sections within the genus:
Braviflores – covering India – Borneo – Java
Calcarifera – mainland Asia, Borneo,Java, Phillipines, New Guinea. These grow at a low to moderate altitude with year-round rain.
Callista/Densiflora – mainland Asia, with a moderate to high altitude and a marked dry season. Usually large flowers and often long pendulous racemes.
Calyptrochilus – mostly New Guinea, altitude from 500m upwards; high rainfall in the rainforests. They flower on bare stems.
Crumenatum – e.g. Dendrobium crumenatum, which grows on trees, just about covering them and produces many flowers which only last a day but continue to come.
Dendrobium – mainly centred in India; low-moderate altitude. Many of these drop their leaves before flowering as they have no scent and pollinators will be able to find the flower more easily without leaves being in the way. Kew Gardens had some large ones which they kept outside for 99% of the time, but they had to be sprayed in the summer.
Dendrocoryne – Basically Australia. Huw said his Den. kingianum plants had been left out all winter (except for one or two days) and they were fine. Some people leave them out but in a polytunnel for the winter. There is the same problems as with garden plants inasmuch as the frost does not seem to hurt them as long as the early morning sun doesn’t get to them before they have recovered from the frost.
Formosae – India through S.E.Asia, Sumatra, Phillipines and Borneo. These flowers are scented 24 hours a day.
Latouria – Philippines – Samoa and centre of New Guinea. They grow at sea level to high altitude.
Oxyglossum – Mainly New Guinea. Medium-high altitude, high humidity. Some of their members grow these successfully, one member grows his high in the greenhouse, seem to be best grown on bark; small plants.
Pedilonum – India, Samoa, central New Guinea.
Phalaenanthe – New Guinea, N. Australia. They grow below 500m in seasonally dry woodland and savannah. Huw said he struggles to grow them in the greenhouse, they do better indoors, maybe because it is always warmer in the house.
Spatucata – Phillipines, Java, central New Guinea – Australia and east to Samoa. Needs humidity, rain and sun, although some like dry areas and a few high altitude.
Hybrids – these are bred to be tough and easy to flower and are sold in supermarkets.
Relatives – previously called Dendrobiums – Epigeneum, Diplocaulobium, Dockrilla, Flickingeria. All grown at sea level, 30º-35º but happy to go down 10 or so degrees.
Growing medium– many do well mounted on cork, hardwood, tree fern etc.; most need to be drier in winter; bark keeps wetter at the bottom and drier at the top, sphagnum dries at the bottom but water rises to the top.
Pruning – some Dendrobiums flower on old stems for quite a few years, these stems store water. So, don’t cut the stems unless they look really dead or are shrivelled – as already said, some flower only on bare stems.
