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 Dendrobium kingianum 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

Dendrobium kingianum (Pink Rock Lily)

This is possibly the best known and most variable of our native epiphytic orchids. Its range is along the coastal strip from the Hunter River in New South Wales to Rockhampton in Queensland. While it is principally a lithophyte and found growing in large mats on exposed rock faces, it is also found in shady gullies and on trees.

It has three to six lanceolate leaves up to 13 cm long on stems varying from slender stems, pseudo bulbous only at the base, to short stout pseudo-bulbous stems. The pseudobulbs are usually 8 to 10 cm long with some up to 30 cm in length; the colour varying from pale green to dark reddish green. One to three racemes of up to twelve flowers, often fragrant, are borne from the top of the pseudobulbs, the colour, while commonly pink, varies from white to purple. They are up to 25 mm in diameter having the labellum usually spotted and blotched with mauve. The flowering season is August to November.

It can be grown on slabs or trees (e.g. Jacaranda or Melaleuca) but locally, best results are obtained from pot culture – rafts or hanging baskets, using an open mix. Some growers use a commercial cymbidium mixture.

I have had good results by lining wire baskets with a thick layer of live spagnum moss and filling them with small pieces of seasoned pine bark and charcoal. I find that the plant not only grows up but also out of the sides of the basket.

Some shade is required in our summer I have had success using 50% shadecloth. Protection from our winter frosts is also necessary. Fertilise lightly in the growing season using commercial fertilisers at half strength.

Being hardy it is well suited to cultivation and hybridisation. D. x delicatum is a natural hybrid of D. speciosum and D. kingianum, also D. x suffusum is a natural hybrid of D. gracilicaule and D. kingianum.

A number of man-made hybrids are available. Some of the best known are D. Bardo Rose (D. kingianum x D. falcorostrum). D. Ella Victoria Leaney (D. kingianum x D. tetragonum), all of which respond well to pot culture and flower freely.*

Propagation is either by division or cultivation of “keikies”.

Drawing of Dendrobium kingianum
Drawing of Dendrobium kingianum

*The number of hybrids has increased since 1983.

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

 

Creating a Mosquito-free Micro Climate for Epiphytes

Adelaide in summer is very dry and hot with very little humidity or rain.  Since January 2015 there has been over 60 days without any significant rainfall.  This presents a problem for growing Australian epiphytes which come mainly from the eastern seaboard with its increased humidity and summer rain.  Therefore to grow ephiphytes in Adelaide, it becomes necessary to attempt to replicate these conditions through creating a micro climate with increased humidity.  To achieve this many growers will stand the pots on gravel in water-filled trays but this presents a problem.  Mosquitoes love it and rapidly breed up to the annoyance of us all.

The following system stops mosquitoes from breeding plus prevents pots getting water logged in Adelaide’s winter, particularly when the pots are not under a solid roof but shadecloth (in this instance, 50% shadecloth).

  • Equipment
    • 10 Black trays – these were inexpensive trays from Cheap as Chips
    • Black irrigation tubing
    • 10 Grommets
    • 11 ‘T’ junctions and 2 angle junctions
    • Tap
    • Sealant
    • Gravel
    • Builders Landscape Fabric
  • Preparing the trays
    • One hole was drilled in each of the trays.  A grommet was placed in each hole and using ‘T’ and corner junctions the trays were joined with poly tubing including a tap.

      The trays connected.  To give stability the trays and hose were connected to the table top.
      The trays connected. To give stability the trays and hose were connected to the table top with the hose running under the table top. This allows free drainage as it stops the hose from being squashed.
  • Checking the system for leaks
    • The next step was to check that the water flowed into all the trays and that there were no leaks.

      Filling all the trays from one tray.
      Filling all the trays from one tray.
    • There were leaks and these were sealed with an aquarium sealant.
    • A hose with a tap was directed toward a raised garden bed on the other side of the shadecloth.

      Checking for leaks & the drainage system
      Tubing leading to the raised garden bed
  • Preparing the inner tray
    • The system requires a second tray.  Drainage holes were drilled in the trays.

      Inner (upper) trays with holes to allow the water to come up into the pots.
      Inner trays with holes to allow the water to come up into the pots.
    • Gravel was placed in the outer (lower) tray.

      Gravel to support the inner trays
      Gravel to support the inner trays
    • The reason was two-fold.  One was to make it easier to remove the inner tray with the pots insitu and the other was to hold the builder’s landscape fabric nearer the inner tray.  The purpose of the fabric is to keep the tubing clear of debris.

      Layer of cloth to stop debris entering the drainage pipes
      Layer of cloth to stop debris entering the drainage pipes
  • The finished system
    • Pots in place and ready to enjoy the new growth of those numerous plants that were divided previously – see the post Breaking up is ….. easy to do.

      The front pot originally consisted of just the pseudobulbs without leaves of Dendrobium kingianum.  After a few weeks in this system, new growth.
      The front pot originally consisted of just the pseudobulbs of Dendrobium kingianum. There were no leaves. After a few weeks in this system, new growth has appeared.
  • Using the system
    • Depending upon the conditions, the mosquito breeding cycle can be as short as four days from egg-laying to the larva emerging as a adult.  As a result, the water is fully drained every four days or less.  This regular drainage of water means that there is no stagnant water left lying around for any prolonged length of time.
    • The trays are allowed dry for a couple of days (less in a heat wave) before refilling again and the pots sit in a small amount of water.
    • By following this watering cycle there are no mosquitoes.
    • The shallow layer of water around the pots provides the necessary humidity.
    • In winter the taps are left open the whole time to prevent the plants from becoming water-logged.

NB This system is not suitable for the terrestrial orchids.

 

 

 

 

 

 

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)

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)

 

 

 

 

 

 

 

 

A Revolution of a Sweet Kind

Ever since the Western world discovered the orchid in the 18th and 19th century there have been enthusiasts wanting to grow them but though an orchid may produce millions of seeds, for they are minuscule, only a relatively small number germinate.  The seeds do not have any stored food and are dependent upon fungi for germination.  This made it difficult for early orchid growers who relied on obtaining specimens from the wild – a most unsustainable practice!

Yet today cultivation of orchids is flourishing.  It is not dependent upon removing specimens from the bush.  In Australia it is illegal.

Today the orchid enthusiast can grow orchids from seeds at home.  The technique, invitro embryo germination, is popularly known as flasking.  It involves growing the seeds in a sterile agar medium to which the most significant ingredient was the addition of sugar.

At the time it was developed by Professor Lewis Knudson (1884 – 1958) of Cornell University in 1922 this method was revolutionary.

 

Reference:

Rasmussen J, April – June 1986, “Contact Dermatitis from Orchids” Clinics in Dermatology Volume 4 Number 2

Below are some examples of terrestrial orchids grown from seeds in flasks.

Flasking Terrestrial Orchid Seeds (3)  Flasking Terrestrial Orchid Seeds (2)  Flasking Terrestrial Orchid Seeds (1)

Photographs kindly supplied by Les Nesbitt.

 

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.

Growing Epiphytes in a Dry Climate

By Kris Kopicki

Adelaide has the reputation of being Australia’s driest city, and with good reason. Despite our record setting weather, it’s not uncommon to see subtropical plants surviving our vicious summers if watering can be maintained. This got me thinking about how much extreme weather our subtropical orchids could survive, provided they were kept reasonably hydrated. That was back in 2008, and at that point, I had no experience growing epiphytes, with my collection comprising solely terrestrial species. Having just moved into a new house, I also had no orchid housing, so my epiphytic experiment was going to need to take place under our easterly facing veranda and surrounding trees. The veranda has a few clear sheets that provide some light throughout the day.

To explore lighting, I used a large piece of weld mesh curved to form a cylinder. A makeshift tree if you will. The idea being that plants favouring higher light can be placed on the north east, and plants favouring shade on the south west. Being quite portable, I could move it around as the seasons change. Species were placed according to my research on their favoured lighting conditions. This seemed like a reasonable starting point.

I chose to grow the majority of my plants on mounts, even though many local growers use pots culture for better water retention. The plan was to eventually construct a shade house for my terrestrial collection, and so any epiphytes were going to need to occupy the only remaining space, the roof and walls. Terrestrial orchids are the top dogs in my collection, so rather than adapting my conditions to suit epiphytes, I was investigating if they could fit in with my plans.

Water was always going to be the big problem with this setup, particularly in summer when the temperatures can be relentless. One of the things that kept coming up in literature was to avoid frequent watering in winter, and particularly to keep plants away from winter rain. I was most puzzled by the last statement, as research on the climate of central and northern NSW revealed that winter rains far exceed an Adelaide winter. Also notable were the temperature averages, which showed that while coastal areas were slightly warmer than Adelaide, temperatures in the hills were often much less. This was great news, as it meant many plants would easily withstand Adelaide winter minimums. I decided the best strategy was to water as frequently as possible, so long as the media was dry between watering. The drying was very important to avoid fungal problems and to avoid saturation of the roots. My watering strategy was going to need to make up for the total absence of humidity during summer, so watering 2-3 times a day would likely be a minimum.

Realising that summer would be the breaking point for my plants, fertilising became a key strategy. The idea being that plants with large healthy root systems could make better use of any available water to get them through our hot days. My search for the best way to fertilise lead me to the decision of feeding a little and often. The reasons cited seemed logical enough. Plants are only able to absorb a small amount of nutrients at a time, so infrequent applications of large amounts of fertiliser would lead to waste, so plants would essentially be starved. I chose to alternate between fertilisers which avoids any nutrient deficiencies that one brand may have over another. Applications were made daily, except one day a week where plain water was used. I used 10% of the recommended dose. The first mix was Manutec Orchid Food, replaced with Manutec Orchid Bloom Booster during spike development. The second mix was a combination of Seasol and Powerfeed. Rainwater was always used to avoid build up of salts, which could potentially be a problem with such a high watering frequency.

The majority of species selected were from central and northern NSW, though species from as far north as Cape York were also trialled. It seemed logical to trial plants that eastern states growers considered easy and progressively move to more difficult species. Some of the species purchased in 2008 include: Sarcochilus x Fitzhart, Sarcochilus falcatus, Sarcochilus olivaceous, Sarcochilus aequalis, Sarcochilus spathulatus and Sarcochilus hirticalcar. These species are quite diverse, some thick and fleshy, others very thin and delicate.

Plants were purchased through winter and spring. Initial results were promising, with good root growth and rapid leaf development once the weather warmed up. A few Sarcochilus falcatus and hirticalcar received sun burn during early spring. While they do like bright conditions, it seems even a mild spring sun can damage them. The plants were then moved to a more sheltered location where only very early morning sun was received. Most of the plants flowered well, with the exception of x fitzhart and hirticalcar, which were too small.

As expected, summer proved to be a challenge. Given that the plants had almost no protection from the record heat of the 2008/2009 summer, they seemed remarkably resilient. Growth came to a standstill, and some root tips burned. During an extended period of temperatures over 40°c, a couple plants of Sarcochilus olivaceous and spathulatus were found desiccated, and some leaf tips burned on Sarcochilus falcatus. I decided that this was probably the limit of what they would handle and brought the plants inside the house during severely hot days.

All things considered, the majority of plants made it through one of our hottest summers with little or no damage. With the onset of cooler weather, leaf growth resumed, albeit a bit slower than during spring. Roots recovered very quickly from the heat damage. With all four seasons now under my belt, my collection of epiphytes rapidly expanded, including species of Bulbophyllum, Dendrobium, Dockrillia, Sarcochilus, Plectorrhiza and Schistotylus.

In August 2009, I purchased a weldmesh shade house from Queensland. It offered a lot of bench space for my terrestrial species, while providing hanging space virtually everywhere. I covered the walls in 50% shade cloth, and 70% shade cloth for the roof. I chose to use white marble chip for the floor. Now at this point you’re probably thinking this sounds quite different to the typical structures used for subtropical orchids in a temperate climate. Typically they are designed with a solid roof or walls, keeping humidity high. The downside to that design is air movement is severely restricted, possibly leading to the well documented fungal problems. In my design, humidity is still quite low during summer, but the shade cloth does restrict airflow, offering some protection from hot drying winds.

The shade house offers better light than the veranda, while providing protection from sunburn. It also has the potential to function as a giant evaporative air conditioner by wetting the walls and floor. Summer soon arrived to test out my new growing conditions. Very minimal damage was incurred. Some placement changes were needed to provide more light for some species, and less for others. Most species incurred some root damage, but they quickly recovered after summer. I used a layer of 50% black shade cloth over the top for protection during summer. Terrestrial pots were no warmer than the ambient air, a good indication that the cover was doing its job.

It turns out there may be good reason why such delicate plants with no obvious water storage mechanism can survive such harsh conditions. It has the unfortunate name of Crassulacean acid metabolism (CAM). Plants produce sugars through photosynthesis. To do this, they need energy in the form of light and carbon dioxide from the air. The leaves are covered in tiny pores called stomata that open during the day to acquire carbon dioxide. While the stomata are open, the plant is vulnerable to water loss through the leaves in hot and dry conditions. CAM plants have solved this problem by effectively delaying photosynthesis until night time, when temperatures are more manageable. A number of studies have been done on Australian orchids to show that many species employ CAM photosynthesis. Despite their resilience to day time conditions, CAM plants are still vulnerable to our extreme summer nights, like January 2009’s record minimum of 33.9°c. I’ve found that hosing down the plants and shade house at night helps to prevent or minimise damage.

The vast majority of species I’ve trialled are still alive and well today. Some are species that experienced growers have told me they find difficult to maintain year after year. Here are some of my observations on a range of species I grow.

Sarcochilus spathulatus

Climate Tolerance: Can be vulnerable to extreme heat, but once a good strong root system is established they seem to be quite hardy. They will show heat stress by dropping older leaves. Some root tip damage can occur in extreme heat, but is harmless.

Lighting: A northerly aspect suits them well. Keep them a good metre or more from the shade cloth to avoid sun damage to the leaves.

Watering & Feeding: They relish my feeding and watering scheme, producing roots twice the width of existing roots prior to purchase.

Growing Medium: Cork produces good results. I have also used Melaleuca species for their slightly better water holding properties and rough bark. Some sparse moss around the roots is helpful to protect them while they establish on the mount.

Growth Habit: Slow root and leaf growth over the coldest part of winter. Leaf growth is quite vigorous once temperatures start moving into the 20’s. Growth slows during very hot weather, usually sometime in January. Growth resumes again in autumn, with a burst of new root growth. Spikes appear around April and flowering occurs during September.

Comments: A fantastic miniature species with small sprays of beautifully fragrant flowers. Once established they are easy to care for if watering is kept up over summer.

Sarcochilus hirticalcar

Climate Tolerance: This species does not seem to adapt to our dry climate. I have achieved good results using a cheap mini hot house inside my shade house. I kept the door closed, but not zipped up to allow minimal ventilation. The temperatures get very hot during summer, but they seem fine with it as long as the humidity is maintained. They will show heat stress by dropping older leaves, and will die very quickly. Root damage can occur if the humidity is too low, even in cool weather.

Lighting: A northerly aspect suits them well. Keep them a good metre or more from the shade cloth to avoid sun damage to the leaves.

Watering & Feeding: They relish my feeding and watering scheme, producing good strong roots.

Growing Medium: Cork produces good results. I have also used Melaleuca species for their slightly better water holding properties and rough bark.

Growth Habit: Growth occurs over the whole year due to the warm conditions of the mini hot house. It is slower over winter, but still quite active compared to other species. My plants were too small to flower last year.

Comments: A challenging species to maintain in Adelaide. Once conditions are favourable, growth is vigorous.

Sarcochilus falcatus

Climate Tolerance: One of the most heat tolerant of the small Sarcs. They will show heat stress by dropping older leaves. Some root tip damage can occur in extreme heat, but is harmless.Lighting: I have grown them successfully in a range of lighting conditions, even with a southerly aspect. Even lighting over the course of the day will keep them from moving towards the strongest light. Keep them a good metre or more from the shade cloth to avoid sun damage to the leaves.

Watering & Feeding: They relish my feeding and watering scheme, producing roots twice the width of existing roots prior to purchase.

Growing Medium: Cork and Callistemon produce good results, but Melaleuca species seem to encourage an extensive root system. Some sparse moss around the roots is helpful to protect them while they establish on the mount.

Growth Habit: Slow root and leaf growth over the coldest part of winter. Leaf growth is quite vigorous once temperatures start moving into the 20’s. Growth slows during very hot weather, usually sometime in January. Growth resumes again in autumn, with a burst of new root growth. Spikes appear around February-March and flowering occurs during September.

Comments: My favourite Sarc. species, I can’t seem to stop collecting different forms. One of the hardiest species, they can be grown outdoors if watering is regular over summer. Regular feeding produces a vigorous root system and masses of sweet smelling flowers.

Sarcochilus olivaceous

Climate Tolerance: Can be vulnerable to extreme heat, but once a good strong root system is established and provided with a shady location, they are surprisingly resilient for a rainforest species. They will show heat stress by dropping older leaves. They can be nursed back to health from quite extensive heat damage, even from loss of the growth tip. Some root tip damage usually occurs in hot weather, but is harmless.

Lighting: A southerly aspect suits them well during summer, however brighter conditions may be needed in winter. Keep them a good metre or more from the shade cloth to avoid sun damage to the leaves.

Watering & Feeding: They relish my feeding and watering scheme.

Growing Medium: Cork produces good results. Moss around the roots is helpful to protect them.Growth Habit: Slow root and leaf growth over the coldest part of winter. Leaf growth is quite vigorous once temperatures start moving into the 20’s. Growth slows during very hot weather, usually sometime in January. Growth resumes again in autumn, with a burst of new root growth. Spikes appear around April and flowering occurs during September.

Comments: An interesting little rainforest species that adapts well to our climate with minimal protection. Plants are commonly sold and cheap, definitely worth a go.

Sarcochilus aequalis

Climate Tolerance: Very tolerant of extreme heat, showing almost no damage.

Lighting: A northerly aspect suits them well. Keep them a good metre or more from the shade cloth to avoid sun damage to the leaves.

Watering & Feeding: They relish my feeding and watering scheme, producing healthy roots.

Growing Medium: Cyathea (Tree Fern) mounts give good results. Some moss around the roots is helpful to protect them while they establish on the mount.

Growth Habit: Quite a slow growing species with virtually no leaf growth over the coldest part of winter, and minimal root growth. Leaf growth resumes once temperatures start moving into the 20’s. Growth slows during very hot weather, usually sometime in January. Growth resumes again in autumn, with new root growth. Spikes appear around May and flowering occurs during September- October.

Comments: A slow but hardy species. Not the most spectacular of flowers, but the foliage looks great against a black Cyathea mount.

Rhinerrhiza divitiflora

Climate Tolerance: Very tolerant of extreme heat. Some root tip damage can occur in extreme heat, but is harmless.

Lighting: I have grown them successfully in a range of lighting conditions, even with a southerly aspect.

Watering & Feeding: They relish my feeding and watering scheme, producing healthy roots.Growing Medium: Cyathea (Tree Fern) mounts give good results. Some moss around the roots is helpful to protect them while they establish on the mount.

Growth Habit: Quite a slow growing species with virtually no leaf growth over the coldest part of winter, however the roots remain active. Leaf growth resumes once temperatures start moving into the 20’s. Growth slows during very hot weather, usually sometime in January. Growth resumes again in autumn, with new root growth. Spikes appear around June and flowering occurs during October.

Comments: Not commonly sold or seen in collections, but quite a tough species. It’s a reliable flowerer, producing masses of spidery flowers. The only downside is the flowers only last for a few days. They have very unique raspy roots and tough leathery foliage.

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