Dendrobiums come from South East Asia in an
area that stretches from Northern India to the
islands off the East coast of New Guinea and
Australia to Polynesia. The latitude where they
grow is important. The Equator runs through the
middle of this territory and here it is always
hot at sea level without any seasonal variation.
However, the plants from north of the Tropic
of Cancer and south of the Tropic of Capricorn
are used to a much greater range of climate,
with colder drier winters and warm wet summers.
It is important therefore to know where every
plant comes from.
There are over a thousand known species of
Dendrobium (pronounced den-dro-bee-urn), and
still more are being discovered in the highlands
of New Guinea. This makes them the second
largest orchid genus in the world after
The shape and form of their stems and leaves
vary tremendously, but the pattern of flowers is
fairly constant ranging in size from very small
to huge. Typically the bases of the sepals are
fused to the foot of the column and the lip base
forming a mentum or 'chin' which often houses
For convenience, we consider cultural advice
under three headings.
Nobile (pronounced no-bill-ay) type or Himalayan
New Guinea plants.
Are some of the easiest to grow but can be a
little difficult to bloom regularly. Their
flowers are showy with colours ranging from
white through pink to purple, and the lip is
often beautifully marked in contrasting colours.
They make magnificent specimen plants. Others
are yellow and brown, while the recently
introduced Yamamoto hybrids have all the colours
of the rainbow. The Himalayan climate is not
unlike a warmer Switzerland, with bright, cold
but dry winters.
November-February: daytime temperatures can drop
to 40° - 45° when you should not water or feed
but give plenty of light and air movement.
March-May or June: warmer and moister
conditions. Buds develop and new growths appear.
Water sparingly until the new shoots have grown
good roots. From June-November corresponds to
the monsoon period, warm and very wet. Give a
low strength, high nitrogen feed in April and
May, then feed weekly during maximum growth.
Change to high potash for the last month. Note
If you do not dry and cool the plants during
winter, you won't get flowers! Himalayan
Dendrobiums from lower altitudes need a less
harsh winter but still dry.
New Guinea Dendrobiums.
The climate varies with altitude and in
mountainous areas there are cool, wet misty
nights and mornings followed by warmer bright
days. The exquisite cool and intermediate
miniatures like D. cuthbertsonii grow here.
Never allow them to dry out completely and feed
often with dilute fertilizer. The river valleys
between the mountain ranges are warmer and
wetter, and home to some of the most exotic of
the New Guinea orchids, e.g. D. lasianthera from
the Sepik River basin, and many Latouria types
with long-lasting flowers. All these need
generous feeding and watering. The southern
plains resemble Queensland but are wetter and
very warm all year through. There is seasonal
rainfall variation with a wetter summer and
Two of the outstanding species from this area
(which are also found in Australia) are D.
bigibbum (D. phalaenopsis) and D. canaliculatum,
the former often found growing on rocks, the
latter on the trunks of paperbark trees. The
easiest New Guinea plants for beginners are
Dendrobium oberrans (cool conditions); D.
lawesii or D. antennatum (intermediate); and D.
atroviolaceorn or D. bigibbum (warm).
Australian Dendrobiums .
Dendrobium Kingianum or near relatives are the
easiest to grow. The pseudobulbs or canes can be
any length from 5cm. to 30cm. tall and are thin,
and often spindly and tough. The leaves are
narrowly oval with 2 to 4 at the top of each
cane. The flowers appear in late winter and
early spring in loose sprays at the tops of the
canes on both the old and new canes.
New plantlets or keikis may sometimes appear
instead. These can be removed and potted
separately after they have developed good roots
or left on the parent plant where they will
eventually flower also. There are two to ten
flowers on a spray, each measuring 1- 3 cm.
across, in shades of pink or purple. Other
plants in this group may be taller and have
yellow, cream or white flowers. For their
culture give intermediate temperatures and drier
conditions than other Dendrobiums. Spray once a
week and water generously in the spring and
autumn with dilute feed. A few cold weeks in
winter (down to 45°F), will encourage flowering.
Dendrobiums like to be in small pots with their
roots confined. Bark, perlag and charcoal make
up an open mix which drains easily. Repot when
either the compost becomes acid and soggy or
when the pot is full of roots. This often means
every year. Plants from the mountains of New
Guinea like a little moss mixed with the bark or
they can be grown on slabs of bark or tree fern
on a mossy bed. Such slabs need daily misting
for most of the year.
There are innumerable Dendrobium hybrids and
these are almost always derived from species
within one group, either Himalayan, Australian
or from New Guinea. Surprisingly, most of the
'Singapore' orchids, although developed there,
are derived from species of New Guinea and the
adjacent islands and need much the same culture
as the River Valley New Guinea species. So, when
you buy a Dendrobium, ask which group it belongs
to and where it comes from - and we don't mean