Sarcs – Growing without the Nonsense!

The following article is from Volume 42 Number 10 November 2018 Native Orchid of South Australia Journal. Marg Paech, editor, has written an excellent summary based upon Kevin Western’s detailed notes which he has kindly supplied and is available here.

1510 sarcochilus cropped

Kevin Western, this month’s guest speaker didn’t hold back. He exposed some of the myths pedaled by good growers who misinform naive newbies or other growers.
Until about 1960 or thereabouts, the only Sarcochilus orchids that existed were in the bush where they had evolved and grown for all time and the only orchids that existed in people’s collection were bush collected so therefore all were species. No doubt, at times in the bush, there were hybrids made accidentally by pollinators or by other natural chance events. 1968 was the first time we can say for sure that there were hybrid Sarcochilus in existence.

Sarcochilus are native to the east coast of Australian and to Tasmania. There are about 25 species recognized and the number has grown recently with the splitting off of S. minutoflos.

The easiest species to grow for hobbyists generally are Sarcochilus hartmannii and S. fitzgeraldii. From their physical appearance and flowering time, flower shape and nature, it can be seen that they are closely related. Their natural environment can be matched in a pot by using a range of different potting materials (either solely or a mixture of) – suitable size pine bark, Perlite, cut up tree fern fibre, rice hulls and or sphagnum moss. Remember, they will grow on rocks, rubble or on various types of natural and artificial mounts!

03 KK sm Sarcochilus falcatus Mt Banda Banda
Sarcochilus falcatus

Humidity

Sarcochilus grow naturally where they do because of the balance between the suitable amount of reliable moisture in the form of rainfall and or dew; and those unavoidable moisture losses due to sun, heat and wind. We can replicate that by just giving our Sarcochilus regular waterings, and ensuring that our potting medium is coarse enough. An extra layer of shade in really hot summers can help, and by reducing wind movement by the location and provision of shade houses, we can create suitable growing conditions for our orchids. Frequent watering is the trick – retirees by hand watering and workers by sprinklers, misters on timers or thermostats or similar. Air movement is a must but here in sunny Adelaide we get plenty of it and in fact, too much movement has a drying effect.

Potting Mixes

The best mix for Cymbidium (sic)* orchids is a coarse, non-retentive medium – far better because they can be watered frequently – even twice a day or far more, and plants do far better. Even standing the pots in water during summer works wonders! Trial and error is the best way to learn, as experienced by Kevin.

Sarcochilus can be potted into clay balls used by hydroponics growers. Good, clean coarse pine bark also is fine.

1510 sarcochilus x velvet

Watering and Fertiliser

It is generally considered impossible to grow plants on mounts in shade houses etc in suburban Adelaide. Yet another myth! They grow exceptionally well, a fact that Kevin found out thanks to Kris Kopiki. It is more difficult to overwater a plant on a mount.

There are lots of myths about fertilizing. Using far more dilute fertilizer applied to a dryish mix and roots, Kevin has found to be far more effective. His policy is to fertilise weakly and frequently. Despite the hundreds of fertiliser options and brands available – they all are only better or worse
sources of those few essential substances which an orchid requires. The seaweed extract products are probably good as they seem to promote root growth. Keep it simple is the best option.

Summary

Our Sarcochilus have roots designed to grow attached to rocks or branches or twigs and are designed to catch and hold quite small water opportunities and they may benefit from drying out from time to time and for periods of time.

Coarser and less water retentive media are advantageous by enabling the roots to experience some drying as would occur in nature.

We are then able to water and fertilise far more often and our plants will grow better. We need to better understand what our preferred fertiliser’s strengths and weaknesses are so that we can better supply their needs more simply, more effectively and at lower cost.

Regular watering, wind control and shade improvement to avoid drying stress is far more sensible than hoping to reproduce and sustain high humidity.

Thank you Kevin for such a candid, down-to-earth talk full of good advice for growers

*In Kevin’s note he discusses his experience with Cymbidiums but Sarcochilus can also be grown with a similar medium.

sarco nugget gold rush seedling (1)edited

2017 September Cultural Notes

Steve Howard’s September Australian Epiphytes and Terrestrials Orchids Cultural Notes for Adelaide’s conditions.

Watering

Epiphytes

Mounts daily. Generally moistening roots only.

Pots weekly. Small pots twice weekly depending on weather.

Terrestrial

Pots can dry out faster on warmer days so keep a watch on conditions. Note some terrestrials will commence summer dormancy towards the end of the month. Those that do show signs can have water reduced somewhat.

Feeding

Terrestrials

Weak organics like Seasol and Powerfeed applied in low doses can benefit colony type greenhoods.

Epiphytes

Low nitrogen always best for native epiphytes. Top up epiphyte  pots with dolomite lime and a dash of blood and bone. Seasol a useful additive now as new seasons root start.

Pests and Disease

Epiphytes

Botrytis will rot new buds in cold damp weather as fast as it attacks new growths from now. Aphids will increase sharply this month and favour new growth and spikes.  Pyrethrum sprays eco friendly and work well, so does a hose but dry spike straight after.

Terrestrials

Some terrestrials will rot this month if conditions have been too wet or stagnant over winter. Note this for next season and add more drainage if this has been an issue.

General Advice

Keep flowering plants under cover to enjoy as can be rather wet and cold as well sunny and warm this month. Start repotting and division once flowering finished to give plants longest possible time to establish over new growing season.

Time to get busy and take note of the jobs of potting and division to be done. Sept and October are the best months to work on the collection before the hot weather sets in.

Do you have small slugs and snails in your pots?  Get a cheap coffee grinder and grind up your snail pellets. Sprinkle in the pot and water them in. Bite size for micro slugs and the baits get right into where they hide.

[Terrestrials are not repotted until summer – Steve will have more on that later]

Pterostylis 'Nodding Grace'

2017 July Cultural Notes

Steve Howard regularly writes orchid cultural notes for various orchid clubs in South Australia. His notes are tailored specifically conditions in Adelaide. The following are his notes for both epiphytes and terrestrials for the month of July.

Epiphytes

  • Water mounted native epiphytes daily; pots weekly and small pots twice weekly depending on the weather. Hot cold types require drier conditions. Generally none to once monthly for me.
  • Colder weather slows down their metabolism in winter. Foliar feeding is beneficial.
  • Keep water out of new growths to avoid rot. Clones prone to this need to be moved under hard roof cover to keep drier.
  • Check under leaves for scale.
Epiphytes in flower (1)
Annual NOSSA Spring Show

Terrestrials

  • Weed pots as the weeds appear and ensure that they don’t get too wet.
  • Remove rotted growths.
  • Start baiting for slugs and snails as spikes emerge from protective sheaths.
  • Provide hard cover during wet weather to stop botrytis spotting and rotting out spikes.

Thelymitra plants in pots

Gleanings From the Journal: Rescuing apparently ‘dead’ orchids Parts 2 & 3 of Three Parts

This week we continue with both Part Two and Part Three of Brendan Killen’s Rescuing Apparently ‘Dead’ Orchids  which appeared in the Volume 31 No 9 October 2007 and Volume 31 Bi 11 December 2007, respectively.

Rescuing apparently ‘dead’ orchids. Part 2 By Brendan Killen

PLANT #2 – Dendrobium Alick Dockrill “Pale Face”

untitled

The cane pieces of this plant were inserted into a bark mix at the same time as the canes of Den. Jayden ‘JANE’ [See the July Journal] were inserted into sphagnum moss. The outcome is three healthy growths.

Note the dried ends of the canes where they were cut into separate pieces. As you can see from the photograph, I used a green twisty to hold the canes in the bark as a fairly solid bunch – I find this is the best way to keep the canes still whilst they are developing sensitive new growths. I have found that no matter how bunched-up the canes are, the new growths always find a way to the surface.

untitled

Here is a different angle on the new growths with my fingers providing some perspective on the size of the growths.

Note that they are significantly larger that those on the Den Jayden ‘JANE’, with the same time in the pots.

I do not consider this evidence of the worth of bark compared to sphagnum moss.

I find that different hybrids and species behave quite differently in terms of their speed and timing of production of new growths. I believe that it is a function of what species are in the background of these plants and the time of year the rescue is undertaken.

Here is the same plant 5 weeks later. The new roots are protruding from the pot and the new growths are extending themselves – all of this at a time where severe water restrictions limit me to two waterings each week by watering can!

Plant 2-3 Den Alick dockrill 'Pale Face'.jpg

Plant 2-4 Den Alick dockrill 'Pale Face'.jpg

A further 4 weeks of cultivation and bright, warm weather has fully extended and hardened the new growths.

The larger growth should produce a flower spike this Spring.

Dendrobium Alick Docrill “Pale Face” (Photographer: Josh Bridge)

TO BE CONTINUED

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 Rescuing apparently ‘dead’ orchids. Part 3

By Brendan Killen

Plant #3 – Dendrobium Sarah Jane ‘Purvis’

This is a plant that the late John Purvis gave me just before he passed away. Because it is a special plant to me, I cut an old cane into three pieces to produce a back-up plant, just in case my piece of the original fell foul of the orchid gremlins.

Journal

As you can see, it is the least developed of the three plants featured in this article. And yet, the parent plant has produced two magnificent new growths in the same period. I feel that the 12.5% of Den. bigibbum and 12.5% of the hot growing Den. tetragonum var. giganteum have influenced this. This new growth has probably been encouraged since the relocation from Adelaide to Brisbane where the temperature differences overnight are more subtle than in the Adelaide Hills where the plants were previously cultivated. The two hot growing species in the plant’s background were probably held back by Adelaide’s much cooler overnight temperatures. Anyway, this is purely conjecture on my behalf. What is important is that I now have a developing back-up plant for one that I treasure dearly.

Dendrobium Sarah Jane ‘Purvis’ (Photographer Josh Bridge)

SUMMARY

The thrust of what I have written is simple – don’t give up on treasured plants that look like they have expired, because there is always hope so long as the canes haven’t turned into fermented mush! The technique is as simple as cutting canes into lengths where you have at least three, preferably four, segments from which new growths will materialise. Use sterilized cutting tools to avoid contamination of the canes. Once the new growths have emerged, give them time to produce healthy root systems and let the new canes harden before potting-on. The best time I have found to pot-on the new growths is early autumn.

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Thank you to Josh Bridge for supplying images of the flowers of Dendrobium Alick Dockrill “Pale Face” and Dendrobium Sarah Jane ‘Purvis’ as they were not in the original articles.

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Another technique demonstrated by John Gay at one of the NOSSA meetings a couple of years ago was to take the apparently dead canes of an epiphytic orchid and seal them in a plastic bag with a small piece of damp sponge (or other cloth) and leave them in the shadehouse.  Do not let the sponge dry out.  So long as there was a bit of moisture, there was a chance for new growth on the shrivelled canes.  Once the growth was obvious, pot on as normal.

GLEANINGS FROM THE JOURNALS: Part 1 of 3 parts Rescuing apparently ‘dead’ orchids

The following is part of a three part series on reviving apparently dead epiphytic orchids from Volume 31 No6 July 2007

 

Rescuing Apparently ‘dead’ Orchids

By Brendan Killen

In late Spring 2006, I had an ‘open shade house’ event at my place in Belair, South Australia. As part of the programme, I demonstrated how I rescue orchids that have all but died. My demonstration was based on many years of experience in not giving in to the demons that cause orchids to expire.

I used two orchids that everyone attending agreed would normally be tossed into the rubbish bin or compost – all bare canes; heavily shrivelled; all new growth ‘eyes’ at the base of the canes chewed out by insects. In other words, an apparently hopeless situation. I’ve never given up on these terminal plants, believing that they still had life in the old canes along as they hadn’t turned to fermented mush.

I also used an apparently ‘dead’ cane from a treasured orchid that I was hoping would eventually produce a back-up plant using the method I describe in the following text.

In one case (Dendrobium Jayden), I cut the canes into a number of segments and stuck them into a pot with heavily compressed sphagnum moss, topped with river gravel to suppress the moss from growing and overtaking the pot. In the other two cases (Den. Alick Dockrill & Den. Sarah Jane), I cut the canes into segments and placed them in a pot of small composted bark.

The following photographs were taken about 3 months after the repotting demonstration and after the plants were relocated to Brisbane. They demonstrate the benefit of the right technique and a ‘don’t give up’ attitude. This technique has not failed me yet, allowing me to rescue many prized plants that have gone on to be show-bench winners.

PLANT #1 – Dendrobium Jayden “Jane”.

Plant 1-1 Den Jayden 'Jane'.jpg

This photo illustrates the emerging new growth on a Den. Jayden “Jane”. This is the first evidence that success is at hand. It is also the first new growth discovered on this plant before I inspect the canes further to see if there are any other new growths buried within the sphagnum moss.

Plant 1-2 Den Jayden 'Jane'.jpg

In this photo, you can see that the new growth is very pale from having emerged from deep in the sphagnum moss with little exposure to light. The juvenile roots can be seen emerging on the right hand side.

Plant 1-2-2 Den Jayden 'Jane'.jpg

A closer inspection reveals another growth, on the other side. Note that both growths are not coming from the ‘eyes’ at the bottom of the canes – simply because they were cut off at potting time. They are emerging from the section that joins the cane segments.

Plant 1-3 Den Jayden 'Jane'.jpg

Teasing away the sphagnum moss reveals even more of the young roots. Note how the new growths are lacking any colour substance at this stage.

If I were to ignore this plant for much longer, the new growths would have rotted in the very moist sphagnum moss, neutralising my efforts. So, the lesson here is to ensure that you monitor the plants for new growths and ensure that you elevate the new growths above the sphagnum moss to give them a chance to ‘harden off’ from their immersion deeper in the sphagnum.

Plant 1-4 Den Jayden 'Jane'.jpg

This photo illustrates how I have re-seated the canes within the sphagnum moss, but much higher so that only the roots are exposed to the heavy moisture content of the moss. I choose to do this instead of placing them straight into a bark mix as I find that the plants tend to go into a shock at the relative lack of moisture in bark and can die quickly, or suffer from stunted growth. I wait until the new growths have matured with substantial green substance before I repot them in a bark mix. And, I tend to do this in late autumn when they are not under any temperature or light stress. By spring, they will be racing ahead in the bark mix with new root growth and, possibly new canes and/or flower spikes.

One Month Later……….

Plant 1-5 Den Jayden 'Jane'.jpg

After one month from the re-seating described previously, note that the pale new growth is now mature and bright green. And, note how the roots are emerging from the growth above the sphagnum moss. This plant will be ready for potting-on into a bark medium in the next few weeks as autumn cools the air in Brisbane.

Plant 1-6 Den Jayden 'Jane'.jpg
Den Jayden ‘JANE’ in flower

This is how I expect it to flower in spring

TO BE CONTINUED …..

Gleanings from the Journals: Dockrillia linguiformis 2006

This week’s blog is an extract from Volume 30 No 10 November 2006.  In this article of Len Field he gives not only cultural notes but also some interesting background including an orchid link with the infamous Captain Bligh.

Dockrillia linguiformis (Sw) 1800 Brieger

Dockrilla linguiformis
Dockrilla linguiformis

Len Field
Common names Thumbnail orchid, Tongue orchid, and in North Queensland the Tick
orchid.
The name linguiforme is from the Latin lingu(a
) as in linguiforme (a tongue). It was also claimed for many years that this was the orchid that Olaf Peter Swartz the German botanist founded the genus Dendrobium in 1800, but this was wrong, although this was the first orchid seen by white man when they landed at the rocks area in Sydney cove, Port Jackson.  It was introduced into England by Rear Admiral Bligh of Bounty fame.
Other names it has been called are
Dendrobium linguiforme var. linguiforme Swartze 1800
Callista linguiforme (Swartze) Rev. Kuntze 1891
Dendrobium linguiforme (Swartze) var. huntianum Rupp 1942
There was another variety named from this species called var. huntianum by Rupp in 1942, which was named after T.E. Hunt and is a June or July flower and found near Ipswitch (sic) in Queensland, but as it reverts to type form it never reached true variety status and was considered just a variation of the type form.
This orchid has a huge range of habitat which stretches from almost the Victorian border up to North Queensland and West to the Great Dividing Range. It is very common throughout this area and equally happy as an epiphyte or a lithophyte but where as a epiphyte it likes swamp oaks (
Casuarina glauca), river oaks (Casuarina cunninghamiana), in fact it will grow on most trees that will hold there bark including the tea trees (Leptospermum species).  I have seen this orchid hundreds of kilometres inland from the coast still forming large mats on the rock faces, while in its more prolific growing areas these mats will cover huge areas of the rocks where it can survive and grow in extreme exposed conditions that would kill other orchids. In the dry times the leaves which are very thick, tough and numerous will shrivel and can last up to six months without water. This is a feature of a lot of Australian Dendrobium and Dockrillia
Flowering is from August to October with blooms that are long lasting, up to two weeks with one raceme per leaf.
Culture. If grown on slabs which is the usual way it should be hung up high and if grown in pots a very coarse open mix. In nature it likes plenty of sunlight although at times it will grow in shade. Whichever way it is grown it should have good light, humidity and air movement.

Den linguiforme drawing
Dendrobium linguiforme


CULTURE NOTES FOR EPIPHYTIC ORCHIDS in ADELAIDE 2016

Dendrobium speciosum

Epiphytic orchids grow on trees or rocks (lithophytic), where they are dependent on their host for support but not for food.

CULTIVATION

The majority of Australian epiphytic orchids can be easily grown in cultivation.  Most can be grown in Adelaide if the correct cultural requirements are provided.  These include controlled glasshouse conditions, shadehouse conditions and, in some instances, in the garden.  Only a few species are able to tolerate the cold winter months in Adelaide without extra protection, and all need protection from frost.

CONTAINERS AND MOUNTS

Plants can be grown in pots or mounted on an appropriate substrate. Pots may be either plastic or terracotta.  Terracotta pots are porous and dry out more quickly than plastic.  If terracotta pots are used, their drainage holes may need to be enlarged to give very good drainage.  Plants should be potted into the smallest pot, which comfortably accommodates the base of the plant.

Plants may be mounted on materials such as compressed or natural cork slabs, branches of rough barked trees, black weathered tree fern slabs and pieces of weathered hardwood.  Brown tree fern slabs contain substances, which are toxic to orchid roots and are not suitable.  Those species that have a pendulous habit e.g. Dendrobium teretifolium should only be mounted.

POTTING MIX

Most potted orchids require a mixture made up of bark chips (fir or pine), to which may be added charcoal, gravel or polystyrene chips, in which to grow.  Bark used should be aged and preferably purchased as graded hammer-milled bark, not shredded bark.  Fresh pine bark contains compounds, which are toxic to orchids.  Before use fresh pine bark should be soaked in water changed regularly, to remove toxins.  This may take 3 weeks.  If in doubt as to the freshness of the bark, treat as above to be sure.

Depending on the size of your plant, bark may vary from 5-7mm up to 20mm in diameter, and sieved if necessary to remove fine particles and dust.  Other substances such as scoria, leaf mould and coarse grit may also be added according to the requirements of the particular species involved.  Whatever the substrate, be it a slab or potting mix, the essential thing with all epiphytic orchids is to always provide good drainage for the plant’s root system.  This ensures no, or minimal, root rot of plants.

Repotting is necessary when the potting mix breaks down resulting in poor drainage, the medium goes stale or when the plant over grows its container.  The best time to repot is during the spring, after flowering, when the plant starts to actively grow again.  Try to repot every 2-3 years.

Potting on:  If the plant has overgrown its container and the mix has not deteriorated, it can be potted on into the next sized pot with minimal disturbance to the root system.

D kingianum composite (2)

GROWING ENVIRONS, HOUSING

Garden Culture

Several species may be grown outside in Adelaide, provided they are given a position sheltered from frosts and hot drying winds.  They should receive daily supplementary watering during the summer.  They may be tied on to trees with rough non-deciduous bark or grown on rocks.  Microclimates can be created in areas of the garden using screens for protection and other plants to help maintain a humid atmosphere.

Bush house, Shadehouse

These structures are built to give protection from frosts, strong winds and sun and to provide extra humidity for plants.  They may be covered with shadecloth or tea-tree and should have a solid south wall.  They provide protection, but still allow for good air circulation around the plants.  A water impervious roof, e.g. fibreglass or polycarbonate sheets, will protect plants and flowers from excess water in the winter.


Unheated glasshouse

An unheated glasshouse gives more protection to the plants, achieving higher temperatures during winter days, and better humidity.  It may be made from glass or other materials such as fibreglass or polycarbonate sheets.  Additional shading with shadecloth or paint is necessary from October to March-April.  Adequate ventilation must be provided, by using ventilators under the benches to let in fresh air, and roof ventilators to let out hot air.  Alternatively, air circulation can be achieved using fans.  All orchids love fresh air.

WATERING

All plants need to be watered frequently from October to April, during the growing period.  Most species require watering once a day or twice a day if the weather is particularly hot or drying.  Ensure that plants dry out between waterings.  During winter, watering once a week should be sufficient for plants in a glass house environment, although plants which are mounted may be misted (a very fine spray) more frequently.  Water early in the morning of winter days to ensure that the leaves of the plants have dried off by night.  Water lodging in leaf axils in cold, comparatively still conditions, renders that area liable to fungal attack.  Humidity may be maintained by watering the floor and under the benches, particularly in summer.

Rainwater, if available, is preferable to mains water, which can. In some cases, increase in salinity to a level, which is harmful to good plant growth.

FERTILISING

To promote healthy growth of all epiphytic orchids, a supplement of half strength liquid fertiliser every two weeks may be used during the growing season of the plant, i.e. November to April.  Mature potted plants can be sparingly fertilised with slow release pellets.  Too much fertiliser will lead to a salt build up (especially in charcoal), which will harm the plants.

PESTS

Pests will become a problem in any shadehouse or glasshouse if the grower does not keep a watchful eye out for them.  The shadehouse or glasshouse should be kept free from weeds, decaying organic matter and rubbish, as these are the places where pests feed and accumulate.  Overcrowding of plants will also encourage pests to thrive.

Pests can be easily removed by squashing if they are in small enough numbers.  A pest strip hung in the glasshouse successfully controls many pests. Unfortunately the environment of a glasshouse, which suits orchid culture, also provides a suitable environment for the spread of pests.  Poisonous chemical sprays should only be used after non-toxic preparations have been unsuccessfully used.  These chemicals also destroy the natural predators of insect pests, upsetting the natural balance.

Caution should be used when handling chemical sprays as many are very toxic to the user as well as the pests.  The manufacturer’s directions and warning labels should be read carefully and recommended strength adhered to strictly.

DISEASES

Australian epiphytic orchids are generally disease free.  Fungal infections may occur, susceptible areas being new growths, especially in young plants.  These can be kept to a minimum by maintaining good air movement and avoiding water remaining in leaf axils for too long.  Broad spectrum fungicides are suitable to control severe infections.

PLANT CARE

Removal of any dead leaves, pseudobulbs, etc, not only enhances the aesthetics of the plants, but also lessens the chance of further deterioration.  These areas are also the places where pests may accumulate or diseases harbour.

Dendrobium bigibbum
Dendrobium bigibbum

Gleanings From the Journal #3 – Native Orchids The Epiphytes: August

The following article is from Vol. 32 No 7 August 2008 Journal of the Native Orchid Society of South Australia Inc.

Dendrobium speciosum
Dendrobium speciosum

Native Orchids. The Epiphytes: August.
Steve Howard

Movement of our natives towards flowering is often rapid.  How often do we look at our plants thinking that they will never be out in time then take a look the week after and they have doubled in size.  Dendrobium speciosum is a classic example of this.  One minute the plant is covered in acorn like flower buds then a week later there are bunches of flowering buds everywhere.  There is the temptation to force them on but I would leave that until the last two weeks prior to show before making that call.  Then we have the Sarcochilus.  These can stay in bud for months and not do a thing then suddenly they are away.

On the epiphyte side we should have a heap of buds everywhere on the flowering plants.  They key is to keep these under cover and away from rain and also slugs and snails that have a nasty habit of chomping into them.  Rain exaggerates fungal problems that will rot out a flower spike overnight.  Also avoid temperature extremes, especially once the buds start showing on a lengthening spike.  Bud drop occurs quickly and the loss of even one bud will sway the judge’s decision.  Even and strong light now becomes important especially for those epiphytes with Den. speciosum and Den. kingianum in the backgroundThe reason is we need to create strong upright racemes to support the flowers.  No point having the spikes hanging over the side of the plant and then have the flowers doing the same.  Some species do have this trait and as such do not make very good parents if this trait is passed on in hybridisation.  I like my flowers to look at me and cannot see the point in lying on the ground and looking up at the plants on the bench.  Strong light will assist this spike development as does the potassium and potash in the fertiliser.  This is also a reason we tend to avoid high nitrogen feeds in our feeding programme.  Even light is also important in order that the flowers will be evenly distributed around the pot as opposed to all facing the one way.  Hanging flowering plants is one way we can get this even light.

Now is also a good time to clean up our plants before flowering.  Remove husks over the canes, remove dead leafless canes and trim and clean the leaves.  It is easier to do this now whilst the spikes are on the small side.  Also give the pots a scrub too.  All of these tips will help make things a little easier when it comes time to prepare the plants before show.  Also make sure you have some fresh topping for the pots.  It’s these little things that helps improve the presentation of our plants.

Only remove leafless canes if you think they have completed their flowering potential as many will flower for years after losing leaves or if the cane affects the appearance of the plant.  If the forward growths are struggling under no circumstance remove the leafless cane unless it is absolutely dead as the struggling plant would be relying on stored nutrients in this cane to survive.  I would then concentrate on why is the plant in the state in the first place.

Dendrobium bigibbum
Dendrobium bigibbum

Even though we are two months away from re potting and dividing our plants it is now time to take stock of what plants will be potted on, divided or sold off on the trading table.  That way we can arrange pots, mix etc in preparation.  The other thing I am looking at now is where am I going to move my plants this year.  Last years heat exposed many plants that are susceptible to heat and with the probability that this will happen more frequently in the future there is the need to move these prone plants from where they are at present.  Leave them where they are and the same thing will happen again.  There will also be the need that these tender plants be removed from the collection and the emphasis placed on more hardy species and hybrids.

Watering will be dependent on the hybrids you grow and where the parents originate from.  Most of the hot/cold type have the tropical hard cane types in the breeding eg Den. bigibbum and these require dry winters so we need to take this into account here.  I do not dry them out completely but then again don’t water them frequently either.  I aim for slightly moist at all times to keep the roots in good condition.  The others with Den. speciosum, kingianum, falcorostrum all come from cooler climates that receive winter rains and as such can handle being damp over winter.  Avoid over wetness as this will be to the detriment of the plants.  These plants require a short dry period after flowering to mimic the same dry spring period experienced in the areas where most of them come from.  I find that with our reduced rainfall of late, nature provides my plants with enough water apart from the mounted plants that get the odd mist or squirt.  Any watering should be confined to the warmer part of the day after lunch.  Early morning squirts with water from a hose that has been sitting on a frozen ground all night will not do your plants any favours.  Feeding during these cooler months is infrequent and if you miss them for a month or more will not cause too many issues.  Plants under cover get watered every couple of weeks and these are usually the hot colds.

You will have a few late season new growths reaching full size.  Keep an eye on these as they are very prone to rot when water sits in the axils of the new growths.  If you notice a growth go reddish or yellow it is a good bet that it has rotted.  You can cut the growth off below the infection and treat with a fungicide.  I then dry the plant out as a precaution and take a mental note.  This plant will always be prone to attack.

My plant of the month is Den. aemulum, the feather orchid.  This compact growing epiphyte comes from central NSW (New South Wales) to Qld (Queensland) and comes in 2 forms.  The iron bark form strangely enough grows on the iron bark tree, a heavily permanent barked member of the eucalyptus family.  It has small cylindrical psuedobulbs that grow in a radial pattern topped with two small and rather thick leaves.  Small white clusters of flowers that go pink as they age are borne apically over several seasons from the one cane.  The other form commonly seen is the brush box form.  This is the long caned variety and the two are found in similar areas.  These are not often seen in collections and have the habit of slowly fading away in cultivation unless their requirements of light, a suitable host and conditions are met.  I have several plants on different hosts and the results are mixed.  The best plant grows east on a slab of hardwood in a rather protected spot and is the brush box form.  The iron bark forms appear to struggle on mounts of Callistemon and paperbark.  Maybe it is the acidic gummy excretions from the bark of the ironbark that are missing.  These plants have not been used in hybridisation very much as they do not have the traits that hybridists are looking for.  Nevertheless I find them a very attractive flower when grown into a specimen plant and they will always have a place in my collection.  They are not easy to obtain and generally restricted to those that have permits to collect them from the wild.

Next month is September and with it the warming weather and a profusion of flowers.  We will look at a few tips to help with the presentation of show flowers but also look back at those that did not flower well or flower at all and see where we can improve and what went wrong.

Epiphytes in flower (1)
Annual NOSSA Spring Show

SHOWY SPECIOSUM

A very popular orchid grown in culture in South Australia is the epiphytic/lithophytic Dendrobium speciosum.  It is a showy species with a heady perfume.

Dendrobium speciosum
Dendrobium speciosum (Rock Lily, Rock Orchid) in culture

This species ranges along the eastern seaboard from Queensland just peeking into Victoria.  There are nine variations each with its own unique distribution.

Map source The Rock Lily Man

But not only is it popular in South Australia, it is popular throughout the country.  The whole of the 2006 September issue of the Orchadian was devoted to a single article on D. speciosum.  The March 2016 Orchadian has three articles plus references to D. speciosum in other articles.

And then there is Gerry Walsh who is so passionate about this species that he has a comprehensive website – The Rock Lily Man – devoted to it.  Explore and enjoy his website.

 

Calliope Range, Sept 2005
Photo source The Rock Lily Man

The Orchid Club of South Australia has produced a fact sheet for growing this species in South Australia.

 

 

Growing Cymbidium canaliculatum 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. 11, December, 1983

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

Cymbidium canaliculatum

A most interesting orchid, also one of the few epiphytes to grow in Western Australia. It is credited with a southern limit of near Forbes in New South Wales, extending northwards to Cape Yorke Peninsula in northern Queensland and westwards across the Northern Territory to the northern areas of Western Australia. Although sometimes found in the near coastal areas of the eastern states it is primarily a plant of the open forests of the drier inland areas. In some of its habitats there is less than a 55 cm rainfall, summer temperatures of over 38⁰ C with a very low humidity and winter temperatures dropping to below freezing. While not exclusively, it is usually found growing in hollow branches or trunks of trees where its roots penetrate the decomposed wood and often grow to considerable length. No doubt the fact that the roots are protected from the heat enables it to survive and even thrive under such harsh conditions.

It frequently grows to form large clumps of crowded pseudobulbs having two to six leaves which are thick, rigid and channelled and are from 10 to 50 cm long and 2 to 4 cm wide. The racemes are up to 50 cm long and can be erect or pendulous with up to 60 extremely variable flowers about 2-3 cm across.

The colours range from green, brown, purple, dull red or a combination of those colours and may be either with or without spotting, the labellum, however, is usually white with red markings.

I find that C. canaliculatum responds reasonably well to cultivation and have grown and flowered it in plastic planters filled with a mix of charcoal, pine bark and rotted hardwood, also in hollow logs filled with the same mixture. Propagation from backbulbs has been with limited success and it looks like about a six year project from planting to flowering.

An established plant can take full sun and will withstand our winter frosts without detriment. Fertilising has been with the occasional dose of liquid fertiliser. When purchasing from a nursery I would suggest medium to small plants as although large clumps may look attractive they usually have had the root system almost completely removed – an operation to which they do not take kindly.

Cym caniculatum drawing

Les adds that Cym. canaliculatum should be kept dry from Anzac Day (25th April) to September when the flower spikes appear.