Growing Dendrobium falcorostrum in Adelaide 1983 and Now

In 1983, Ron Robjohns, NOSSA’s first treasurer, wrote a comprehensive series of articles about growing epiphytes in South Australia. Thirty years on Ron’s information for growing is still helpful and applicable for today. Any updates or extra information are in black text.

NATIVE ORCHID SOCIETY OF SOUTH AUSTRALIA JOURNAL

Volume 7, No. 5, June, 1983

GROWING EPIPHYTIC ORCHIDS IN SOUTH AUSTRALIA – R.T. Robjohns

Dendrobium falcorostrum (Beech Orchid)

This is one of the most attractive of the New South Wales epiphytic orchids, the common name being derived from the fact that it is only found in the forests of the Antarctic Beech, which occur in the highlands, extending from the Barrington Tops in New South Wales northwards to the McPherson Ranges in southern Queensland. However, within those forests it does occasionally grow on other than beech trees.

Due to the clearing of those forests it is fast becoming an “endangered species”.

It is a plant of the highlands and is rarely found below 900 metres, consequently it will tolerate cold conditions, however, it requires protection from frosts and needs to be grown where there is plenty of air movement.

There are from two to six light green lanceolate leaves at the top of the stem which is from 12 to 50 cm high and the mature stems are ribbed. The flowers number from four to 20 in the raceme and are intensely fragrant during the warmer part of the day. They are from 3 to 5 cm in diameter.

Flower spikes are terminal and some stems will flower for two or three years.

They are a glistening pure white to cream with the exception of the labellum which is streaked with purple. The common name is derived from the labellum, which is short and broad, bearing a fanciful resemblance to a falcon’s beak. The flowering season is from August to October.

It can be grown using either slab or pot culture using a mixture of aged pine bark, scoria* and charcoal* in a plastic pot and grown under 50% shadecloth.

Fertilise lightly during the growing season using foliar fertilisers at half the recommended strength.

Propagation is usually by division. 

*NB Charcoal is no longer used and scoria can get cold and wet in winter.

Dendrobium falcorostrum
Dendrobium falcorostrum

Growing Dendrobium linguiforme in Adelaide 1983 and Now

In 1983, Ron Robjohns, NOSSA’s first treasurer, wrote a comprehensive series of articles about growing epiphytes in South Australia. Thirty years on Ron’s information for growing is still helpful and applicable for today. Any updates or extra information are in black text.

NATIVE ORCHID SOCIETY OF SOUTH AUSTRALIA JOURNAL

Volume 7, No. 4, May, 1983

GROWING EPIPHYTES IN SOUTH AUSTRALIA – R.T. Robjohns

Dendrobium linguiforme (Tongue Orchid)

The plant is epiphytic or lithophytic, forming large masses on trees or rocks. Its range is from the extreme south-east of New South Wales to at least the Burdekin River in Queensland. It grows from sea-level to altitudes of around 1000 metres, but is confined mainly to the coastal areas, although it has been found up to 250 kilometres inland. The inland plants have smaller, tougher leaves than those of the coastal areas, due no doubt to the harsher conditions under which they exist. It is not confined to a specific host but is found on quite a large variety of trees.

The rhizomes are prostrate and branching with thick, tough ovate leaves, 3 to 4 cm long having distinctive longitudinal furrows on top.

The racemes, up to 15 cm long, grow from just below the base of the leaf and bears from six to 20 flowers. The flowers are usually white or cream with a number of faint purple markings on the labellum.

The flowering time is usually August-September here but earlier in the tropical areas.

It does not lend itself to pot culture but is very hardy and with a little care will grow freely on cork or hardwood slabs. I have had good success using pieces of Melaleuca on which it readily establishes itself. It receives approximately 75% shade. It should be protected from our frosts and can be fertilised using foliar fertilisers at half the recommended strength.

This is the variety of the species on which the genus Dendrobium was founded. It was first described by O. Swartz.

There are three varieties of this species, the best known of which is var. nugentii, which is a tropical form from about the Burdekin River north to Bloomfield River in the south-east of Cape York Peninsula.

This form has broader, thicker leaves which are more rounded at the apex and in addition to the longitudinal furrows it often has transverse furrows. The flowers of this form are slightly smaller and age quicker.

Dendrobium linguiforme
Dendrobium linguiforme

Growing Epiphytic Orchids in Adelaide 1983 and Now

In 1983, Ron Robjohns, NOSSA’s first treasurer, wrote a comprehensive series of articles about growing epiphytes in South Australia. Thirty years on Ron’s information for growing is still helpful and applicable for today. Any updates or extra information are in black text.

NATIVE ORCHID SOCIETY OF SOUTH AUSTRALIA JOURNAL

Volume 7, No. 3, April, 1983

GROWING EPIPHYTIC ORCHIDS IN SOUTH AUSTRALIA – R.T. Robjohns

Epiphytes usually grow where there is plenty of air movement, ample light but also shade and to achieve this they are frequently found well above the ground storey in the forest from where, should they be dislodged from their host and fall to the forest floor they wither and die. With most plants the roots grow downwards, however, with epiphytes in their natural habitat, the roots may grow up, down or around their host, that is, in any direction in search of suitable conditions.

As a novice grower I urge you to learn all you can about the natural habitat of the plant and its principal host, bearing in mind that in accounts of plants that grow on rock faces, often they are growing with their roots in crevices into which any moisture drains and maybe in an accumulation of leaf litter. Frequently the rocks on which the lithophytic orchids grow are sandstone – a rock which can absorb moisture and consequently keeps cool longer than most other rocks. “In an exposed situation” should not be construed as being in full sun all of the time: usually they receive some shade.

With the possible exception of Cymbidium canaliculatum few epiphytes grow at their best in full sun in nature. Full sun in the hot dry South Australian summer will usually burn off the plants or at the best cause severe yellowing and loss of leaves. It is to be noted that this State has no native epiphytic orchids.

Most Australian epiphytic orchids grow in the coastal belt of northern New South Wales and Queensland where the average rainfall in their DRY season is much the same as the Adelaide winter or WET season with which it coincides, consequently advice that plants require to dry out during the winter should not be taken to the extreme and the plants left without water.

The three principal requirements of epiphytes are a free air circulation, a semi-shaded position and free drainage.

In South Australia epiphytes are grown in two ways, the most popular being pot culture and the other slab culture.

For pot culture the medium must be a free draining one and a mixture of “aged” pinebark, scoria and charcoal is quite effective.

Note 2015 – Today the potting media used is composted pine bark.  Charcoal is not used and scoria can get cold and wet in winter.

In choosing material for slab culture consider the conditions under which you intend to grow the plants. For humid conditions cork is ideal while tree fern, which holds moisture longer, is good for dry conditions, although any of our native trees with papery or corky bark is suitable. Perhaps you would wish to attach the plants directly to trees in your garden, for this purpose try Jacaranda, Melaleuca or trees with a similar bark.

Watering is important, slab culture requires more watering than pot culture and in summer water orchids on slabs at least every second day and every-day during a hot spell. Water according to the weather and watch for signs of stress – in wintertime the rain is usually sufficient.

Fertilising is best done using half of the recommended strength of commercial proprietary fertilisers.

As a last general recommendation – beware of frosts. Last year (1982) the frosts in some areas of Adelaide caused severe losses amongst plants of epiphytic native orchids. Large tubs of D*. speciosum, whose thick leathery leaves I mistakenly thought frost resistant, were reduced to a mass of leafless canes; even baskets of D. kingianum hanging three feet below the 50% shadecloth had all of the leaves burnt off. These were but two of the varieties which suffered, so be warned and ensure that your plants are protected from frosts.

*D. = Dendrobium

Dendrobium speciosum
Dendrobium speciosum in culture

 

Three Key Starting Points for Successfully Growing Australian Orchids

There is a lot of information on growing orchids so much so that it can become overwhelming.  As a novice, I’ve put together my observations which can be summed up in three key points.

One – Find a Mentor

The best and first thing to do is to join a local orchid club, such as the Native Orchid Society of South Australia (NOSSA), and find a mentor within the group.  There are many books but nothing substitutes for that personal interaction with an experienced grower who will know both the plant and the adaptions needed for the local conditions.  At the monthly meetings, NOSSA has a Grower’s forum where various aspects of growing orchids are discussed and questions answered.  It is well worth attending.

Two – Have an Equipment Kit

There are some things that are essential and it is good to have a basic kit to get started.  Later, more equipment can be added as one’s skill develops in growing orchids.  The necessary items would include:

  • Secateurs
  • Labels – these can be proper plant labels from a garden store or wooden lollipop sticks, so long as they are waterproof.
  • Pen – indelible ink pen or pencil (there are pencils that can write on plastic) as it is pointless having a labelled plant with the details washed off.
    • it may be necessary to use both current name and synonyms on the label eg Corybas/Corysanthes
  • Wettable Sulphur – necessary for guarding against diseases and is available from garden centres but Tomato Dust can be a good substitute although it is half the strength.
  • Sterilizing equipment
    • Good nursery hygiene techniques are important
    • Dilute bleach, tri-sodium phosphate (and possibly a small blow torch for metal tools)
    • newspaper
      • a different sheet for each orchid when dividing will help prevent transference of any disease, etc (don’t forget handwashing)
  • For Epiphytes
    • Ties and Stakes
  • For Terrestrials
    • Sieve for recovering tubers
    • Sheoak or pine needles for putting on top of the pots to stop soil and fungi splashing up on the undersize of the leaves
  • Pots – do not need to be fancy but the pot size will depend upon the species
    • Diuris prefer deeper pots; Corysanthes prefer wider, shallower pots whilst Pterostylis doesn’t seem to mind either

Three – Work within the Plant’s Growing Condition

This will require time, research, experiment and going back to the experienced growers.  Each one of us eventually needs to find what is the best setup for our individual location but some general guidelines would be:

  • Start with plants that are suitable for your current climatic conditions.  Obviously putting a tropical Dendrobium bigibbum under the patio in temperate Adelaide is not going to be successful.  For the terrestrials it is better to start with Pterostylis curta or a Microtis than a fungi dependent Arachnorchis tentaculata.
  • Research the plant you want to grow and then create the micro-climate necessary for the flourishing of the plant.  This will entail separating the orchids, don’t put shade lovers such as Corysanthes with those requiring brighter light eg the Thelymitra genus.
Dendrobium speciosum
Potted Epiphyte – Dendrobium speciosum
Thelymitra plants in pots
Potted Terrestrials – Thelymitra (Sun Orchids)

Australian Orchids & the Doctors they Commemorate Part 17 of 20

Hugo Flecker (1884 – 1957)

A pioneer Australian radiotherapist, radiologist, general medical practitioner and toxicologist of Cairns (Queensland) who dug his own radioactive ore at Radium Hill (South Australia), a medical graduate from the University of Sydney, and a natural historian; his life and works are commemorated by the Flecker Botanic Gardens in Cairns.

Orchids

Cestichis fleckeri (= Liparis fleckeri) Slender Sphinx Orchid

Thelychiton fleckeri (= Dendrobium fleckeri) Apricot Cane Orchid

Australian Orchids & the Doctors They Commemorate Part 16 of 20

Hereward Leighton Kesteven (1881 – 1964)

A general medical practitioner, medical scientist, zoologist, pioneer of industrial medicine in Australia, and national medical director of the Allied Works Council during World War II.

Orchids

Dendrobium kestevenii  is the name applied to the hybrid between D. speciosum subsp. speciosum and D. kingianum

Breaking up is …. easy to do

Attempting to divide a large Dendrobium taberi  (Dendrobium speciosum var. hillii or Thelychiton tarberi) for the first time can be daunting but with a little instruction and guidance it is not quite as hard as it seems. If left, these plants just get bigger and bigger ……

Den tarberii pre-repotting (4)

… and if you would like to see a magnificent one that’s in flower, click here.

Here is my first time attempt at dividing a Dendrobium tarberi.

  1.  First the pot was allowed to dry out a bit – no watering in the days before.
    • A drier plant is easier to divide.
  2. All the necessary equipment was assembled before starting
    Equipment (3)
    Assembled equipment including Snail repellent, Bleach for cleaning pots & equipment, wettable sulphur for putting on the fresh cuts
    • All equipment to be used was disinfected.
    • For though tough, the plants will be placed under stress making them vulnerable to the risk of infection.
  3. The pots were washed in bleach as per instructions on the container, including the wearing of gloves.
  4. The plant was removed from the pot by
    • by giving the pot some good knocks with a mallet. This loosened the plant and made it easier to remove without damaging the pot
    • and then it was given a good shake to remove the loose potting mix
  5. Next the plant was examined for areas of natural cleavage which were then pulled apart.
    • This is the place to start dividing the plant.
  6. The plant was still quite big so then tried using a mallet to try and loosen the plant and find more natural cleavages but wasn’t successful
  7. The whole plant was picked up and dropped from chest height several times
    • This finally caused the plant to split
  8. As the plant started separating two techniques were employed
    Dividing the plant
    These plants are tough – no need to use kid gloves
    • An axe and mallet were used to lever the larger divisions
    • Smaller divisions were twisted by hand
  9. Throughout the process old roots were pulled off or cut away
    • Old roots are soft, spongy and dirty looking
    • New roots were white and firm to touch – see photograph above
  10. Once the initial canes were divided they were examined for further division This decision can be a case of personal preference.
    • In the picture below this section could have been split in half but it was decided to leave as one pieceTo divide or not divide any further
  11. Next the split canes were well dusted with wettable sulphur
    • To make this easier the sulphur was put into a stocking and used like a powder puffSulphur dusting before potting (4)
  12. Before commencing the potting on, many of the dried white sheathes on the canes were removed
    • This can be a source of stagnant water collection resulting in rotting or infection
  13. Finally it came to potting on. A mixture of two types of orchid potting mix was used – Orchid Mix with fertilizer and Orchid mix with 8 – 18 mm bark
    • The reason was that the mixture needs to be open to allow air movement. Normal potting mix would be too compact. Dendrobium are epiphytes not terrestrials but they can be grown in pots.
  14. The canes were placed upright in the pot and the mix placed around.
    • As these are heavy plants, stakes were used to secure the canes upright
  15. Each plant was then labelled
    • An important process so as to not get them confused with other plants – many can look similar
    • The name and date were written on lollypop stick
  16. Finally the pots were given a light fertilizer, less than a teaspoon, and watering, then sprayed with Escar-go, a copper spray a snail and slug repellent.

 

Other grower may do things a little different from what is describe here but this is the method that was shown to us.

Lesson – breaking up is easy to do even if it is hard work, but worthwhile hard work.

The finished product - lots of lovely new plants!
The finished product – lots of lovely new plants!

PS – It did take three of us to do the one pot and so I would like to thank Jan and Sandra for their help.

PPS – Encouraged by how easy it was to do, the following week two of us divided two other Dendrobium –  D. speciosum and D. kingianum (white) but we only took pictures of the D. kingianum and to see what it will look like when it flowers, click here.

D kingianum composite (2)

 

 

 

 

 

 

 

 

Australian Orchids and the Doctors they Commemorate Part 3 of 20

To learn a little more about some of the orchids Professor John Pearn has mentioned, click on the links

Part 3

Early orchidology in the Asia–Pacific region

The fleshy pseudobulbs (thickened stems that serve as storage organs) of orchids have been eaten and used medicinally by Indigenous Australians for thousands of years. The first Australian orchids brought to the attention of Western science were three species of Dendrobium (D. discolor Lindley [described by John Lindley]; D. canaliculatum R.Br. [described by Robert Brown]; and D. rigidum R.Br. [described by Robert Brown]) that were collected by Joseph Banks and Daniel Solander at the Endeavour River between 17 June and 3 August 1770. Solander had trained in medicine and botany under Linnaeus in Uppsala (Sweden) and, after 1759, in London (England). One of the plant species named after him is the Australian orchid Orthoceras solandri (also known as Orthoceras strictum).

Scale on Dendrobiums

Question:

I have scale on my Dendrobrium kingianum.  How do I to treat it?

Answer:

A dilute mixture of eco oil and water is safe to use on Dendrobriums. Use a mist spray bottle and follow up two weeks later with a second spray to kill the hatchlings.

Alternatively you can drench the plant with “confidor”, a systemic insecticide.