Gleanings from the Journals: Terrestrial Potting Mixes

The following article by Les Nesbitt was published in May 2017 Native Orchid Society of South Australia Journal Volume 41 No 4. The article relates to Australian Native Orchids.

Suggested potting mixes for potted native terrestrial orchids have changed greatly over the years as some ingredients such as peat moss have become too expensive or difficult to obtain. Basic requirements are that the mix should be free draining yet retain moisture and should have an organic component that breaks down slowly and does not go mushy in winter. Most species are not too fussy and will grow in a variety of mixes.

Those tubers that desiccate in summer do better in a heavy mix that contains clay. Examples are Diurus behrii, D. punctata and Pterostylis nutans.

Tubers that rot easily in wet soil in Spring prefer an open coarse sandy mix. An example is Thelymitra antennifera.

A dry mix containing a higher proportion of sand is usually recommended for Caladenia and Glossodia species grown in pots. In contrast these orchids grow in clay soil on my property in the Adelaide Hills but there excess water can run off. In pots, excess water has to drain through the potting mix.

An organic component is vital to feed orchid fungi.

Some Basic Ingredients:

  • Washed sand with rounded particles. (Not sharp sand as this sets hard in summer.)
  • Soil (sandy loam, clay based loam, mountain soil)
  • Native seedling mix (Bark based – sieve to remove splinters)
  • Native potting mix (can be sieve* to remove larger particles)
  • Chopped and sieved* gum leaves
  • Perlite or isolite (but will make tubers harder to identify at repotting time)
  • Composted leaf mould & buzzer chips (but needs to be gathered now for use next summer)
  • Cauarina (She-oak) needles chopped for surface mulch

Some Suggested Potting Mixes

  1. ANOS-Vic dry mix – 2 parts coarse sand, 1 part coastal sandy loam, 1 part composted buzzer chips, 1 part leaf mould
  2. 100% native potting mix. (Works for drought resistant tubers, viz. Pterostylis curta & P. pedunculata)
  3. Native potting mix (sieved*) and isolite
  4. Native potting mix and sand
  5. Les Nesbitt’s current mix of 50% sand, 20% hills soil, 25% seedling potting mix (sieved), and 5% chopped & sieved* string bark gum leaves.
  6. Dry mix, 50% coarse sand, 25% perlite & 25% native potting mix
  7. Heavy mix, 50% clay soil, 30% sand and 20% organic matter

* Use a 5mm sieve

thelymitra-plants-1.jpg

Thelymitra in cultivation

2017 April Winning Picture

1704 LN Diuris behrii sm

April’s theme was yellow and orange. All of the entries proved to be spring flowering. There were several Diuris. Claire Chesson, Rob Pauley and John Fennel all entered D. orientis; Les Nesbitt and Rob Pauley D. behrii and Pauline Meyer D. corymbosa from Western Australia. Pauline also entered Caladenia caesaria subsp. maritima and John Thelymitra benthamiana.

The winning picture was Les Nesbitt’s D. behrii (Cowslip Orchid) which occurs in Victoria, New South Wales, Australian Capital Territory whilst in South Australia it is rated as vulnerable.

Les Nesbitt has been working on a recovery project of these orchids for Hillgrove Resource’s flagship, the Kanmantoo Copper Mine, located almost 55 KM from Adelaide. As this orchid is often mentioned in NOSSA Journals, it might be worthwhile looking at the person after whom this species was named.

First collected by German born Dr Hans Herman Behr (1818 – 1904) who first visited* South Australia in 1844 when the colony was barely 8 years old. During his two years in South Australia he became the first person to systematically study our botany and entomology sending reports and samples back home. The results of his observations were published in various journals, and many of his collections were named and described by other botanists including his friend, Diedreich von Schlechtendal (1794 – 1866) who named Diuris behrii after Hans.

Hans Behr was an interesting man. A man of many aptitudes; medical doctor, entomologist, anthropologist, botanist, duellist, socialist, poet, novelist, linguist, member of the Bohemian Club of San Francisco and a man of wit. From the many reminiscences written about him, it would appear that he was a likeable gentleman and a generous teacher.

Unfortunately, not everyone liked him because “he was a sworn enemy of all scientific humbug, of quacks and false pretenders” and “he never refrained from expressing his opinion of them, quite regardless of person or station” but his humour shone forth in dealing with them. Once he named a “particularly obnoxious louse” after one of his enemies.

Behr revisited South Australia in 1848 during which time he became acquainted with German-Australian botanist, Ferdinand von Meuller. He maintained friendship with many of the scientific men of the time including Ferdinand Mueller and it was through this friendship that many Australian plants were introduced into California where Behr later settled after his travels.

Though the study of butterflies was his first and enduring love, he is remembered and honoured in Australia for his botanical interests. Of the twenty-two plants named after Behr, two are orchids: Diuris behrii and Arachnorchis behrii (synonym Caladenia behrii).

*The Journal incorrectly stated that he visited South Australia with his friend, Diedreich von Schlechtendal. This did not happen. As far as I am aware Schlechtendal did not visit South Australia.

Reference

https://archive.org/details/doctorhansherman00cali

https://archive.org/stream/jstor-1630874/1630874_djvu.txt

https://en.wikipedia.org/wiki/Hans_Hermann_Behr

https://www.anbg.gov.au/biography/behr-hermann.html

Kraehenbuehl, D. N., Dr HH Behr’s Two Visits to South Australia in 1844-45 and 1848-49, J. Adelaide Bot. Gard. 3(1): 101 – 123 (1981)

Bates, R. J., ed. (2011). South Australian Native Orchids. Electronic version, 2011. NOSSA

It Finally Happened …

“The person who first records the whole pollination event will be very lucky indeed.” So wrote Bob Bates (South Australia’s Native Orchids, 2011). He was referring to the pollination event for Bearded Greenhoods in the genus Plumatichilos. As with many orchids there has always been a lot of conjecture about the pollination strategy involved so it is good to finally have photographic evidence of a previously unknown pollinator.

For several years now Rudie Kuiter, Mitchell Findlater-Smith and Rober Lindhe have been researching the relationship between orchids and insects, spending much time in the field observing and photographing the insects. Finally they have managed to obtain a photograph of a pollinator but it was not one of their photographs. Instead it was Neil Blair who took the photograph and observed a dagger fly pollinating a Plumatichilos. The male of these fascinating insects catches another insect and offers it for a nuptial gift to a female in order to be accepted as a mate. The photographs are amazing. It’s worth reading the paper Pollination of the Bearded Greenhoods (Orchidaceae) by Dagger Flies (Diptera: Empididae) just to see the pictures.

plumatochilos-sp-woodland-sm

Returning the Water

Each month the Native Orchid Society of South Australia has a special speaker. April’s speaker was Mark Bachmann from Glenelg Nature Trust. He spoke on the The Hydrological Restoration of Glenshera Swamp, Stipiturus Conservation Park.

At time of settlement swamps were common on the Fleurieu Peninsula but now they have almost all but disappeared. This has come about because of the clearing of land for farming beginning in the 1940s. There are now very few swamps left in the area. As a result in this region, the swamp orchids potentially face extinction.

BUT Mark’s talk was a good news story. In April, the Glenelg Nature Trust with the help of the Conservation Volunteers Australia (a Green Army program) began the work of reinstating the original creek by the judicious placing of regulating structures along the principal drain.

The good news is that the water returned as they were building the structures.

It was also a good news story because of the cooperation of different groups including a local land owner who was willing to have some of their land returned to swamp and no longer be available for their horses to graze.

We look forward to seeing the swamp refill and learning how the orchids respond.

Below are some of the orchids found at Stipiturus. Click on the images to go to the three articles documenting the work at Glenshera Swamp.

Thelymitra cyanea

Thelymitra cyanea

Cryptostylis subulata 008

Cryptostylis subulata (Moose Orchid)

Prasophyllum murfettii sm

Prasophyllum murfettii (Denzel’s Leek Orchid)

2017 March Winning Picture

As part of 40th NOSSA anniversary, the theme for this month was Leptoceras menziesii (Hare Orchid or Rabbit Ears). Entries were received from John Badger, Pauline Meyers, Robert and Rosalie Lawrence, with John Badger’s being declared the winner.

1703 sm JB Leptoceras menziesii

In February 1978, it was announced that the nascent NOSSA society required an emblem. Members were invited to send in drawings, to be judged by members and then ratified by the committee. Mrs Chris Butler (Ron Robjohns’ daughter) was the winner. The first Leptoceras menziesii flowers to be benched at a NOSSA meeting were in September 1978. It appears to be an easy plant to grow but a most difficult one to flower.

This seems to be because it is fire dependent. In spring, it will flower profusely if there has been a summer fire such as occurred after the 2015 Sampson Flat (SA) fires. It is possible that the gas ethylene produced during a fire event may initiate the flowering response.

Otherwise, apart from the occasional flowering plant, it will be mainly leaves that are found when out in the field. The single leaf of this plant lying prostrate along the ground is distinctive. It is firm, boat-shaped, glabrous (no hairs), with a fine ‘snake-skin’ pattern. Interestingly, sterile plants can be mistaken for a plant with a developing bud as there will be at the leaf base a ligule (a thin membranous growth, often found on grass stems).

 

Reference

Backhouse, G, et al (2016) Bush Gems: A Guide to the Wild Orchids of Victoria Electronic version

Bates, R. J., ed. (2011). South Australian Native Orchids. Electronic version, 2011. NOSSA

Lawrence, R. W., (2011) Start With The Leaves

NOSSA Journal Volume 2 No 6 July 1978

NOSSA Journal Volume 2 No 9 October 1978

Born to Fly …

Orchid seeds are minute …

… like dust particles.

Orchid seeds are produced in the thousands …

… like dust particles.

And like dust,

Orchid seeds are born to …

… FLY!

 

OLYMPUS DIGITAL CAMERA

Dust-like seeds of Pterostylis nutans

So what do they look like? Amazingly Johann Georg Beer (1803 – 1873), an Austro-Hungarian orchidologist and explorer published in 1863 Beitra ¨ge zur Morphologie und Biologie der Familie der Orchideen. In it, Beer had produced in exquisite detail illustrations of orchid seeds. Beer was not the first to draw orchid seeds but his “drawings are morphologically accurate and artistically magnificent. Beer’s artistic ability, patience, and botanical expertise are obvious. His are probably the first detailed colour renditions of orchid seeds and seedlings to be published.”*

Fig-1-Orchid-seeds-Beer-1863

Seeds_of_orchids_(J.G.Beer_-1863)

Reference

*Arditti, J, 2008, An history of orchid hybridization, seed germination and tissue culture, Botanical Journal of the Linnean Society June 2008

https://www.researchgate.net/publication/229790264_An_history_of_orchid_hybridization_seed_germination_and_tissue_culture

Watering When: cauline type Pterostylis

A common question asked is when to water terrestrials. The short answer is to keep them dry over summer but there are variations such as was previously posted about the watering regime for Chiloglottis. In the March 2017 NOSSA Journal, Les Nesbitt’s article highlights another watering variation.

Blue Tags

Les Nesbitt

Jane Higgs’ lovely pot of the red form of Pterostylis coccina in flower had a blue tag. Jane explained that a blue tag meant that watering had to commence in January for that pot and not at the end of February as is normal for most terrestrials. Start watering later and there will be no flowers. Her pots are under a solid roof. She explained that in the ANOS Vic cultural booklet (Cultivation of Australian Native Orchids) there is a list of cauline type greenhoods which she tags with blue, and includes Pterostylis decurva, aestiva, laxa, coccina, revoluta, reflexa, truncata, robusta, alata, and fischii. To this list can be added abrupta and also the rosette types ophioglossa and baptistii which shoot early.

I have trouble growing and flowering this group of Autumn flowering greenhoods. I went home and dragged out my ANOS Vic booklet and brushed up on the notes. I found several old blue labels in the shed and cut them into strips. I now have blue labels in my pots and the pots are grouped together in the shadehouse where they get afternoon shade. They were given a thorough watering but it will be too late to expect flowers this year. I find large tubers of this group rot easily in Spring and the plants go dormant earlier than other greenhoods. I will try to remember to move the pots under cover in September to let them dry off.

Diplodium in cultivation

Diplodium robustum – one of the cauline greenhoods

Having a visual reminder would certainly make it easier to know when and which pots to water. Obviously other coloured tags can be used instead of blue, so long as they stand out from the label.

 

More on Photographing Orchids

Previously we have posted about photographing orchids for identification – see here and here. But sometimes all that is desired is a beautiful picture of these exquisite flowers. Recently, March 21, 2017, National Geographic published just such an article titled How to Photograph an Orchid.  Author Alexa Keefe relates some tips from German photographer Christian Ziegler. Needless to say half of the images featured are Australian orchids.

Below is a selection of some of the entries to NOSSA’s monthly picture competition.

Caladenia procera

Caladenia procera

 

1608-sm-cc-pheladenia-deformis

Pheladenia deformis

 

1609-sm-bs-pterostylis-cucullata

Pterostylis cucullata

1702 sm CC Cryptostylis subulata

1605 sm PM Caladenia flava

Caladenia flava

1604 sm JB Chilglottis reflexa

Chiloglottis reflexa

 

2017 February Winning Picture

1702 sm CC Cryptostylis subulata

The first competition for the year followed a wet orchid theme with three of the orchids being South Australian swamp orchids and the fourth from Western Australia; though not a swamp dweller, it grows in shallow moist soil.

The outstanding winner was Claire Chesson’s Cryptostylis subulata, followed by Robert Lawrence’s Spiranthes alticola, Rosalie Lawrence’s Pterostylis falcata and Pauline Meyer’s Thelymitra villosa.

Known to South Australian’s as the Moose Orchid, elsewhere it is either Large Tongue Orchid or Cow Orchid. This tall (40 to 110 cms) evergreen orchid is common in the eastern states where it is commonly found in damp areas as well as swamps. but in South Australia it is limited to swamps and is rated as endangered.

Leo Davis makes some interesting observations about the structure of this flower in his article Upside Upside Down which is well worth reading (https://nossa.org.au/2017/03/03/upside-upsisdedown/).

Whilst not an easy orchid to grow it has been cultivated although seed set has not always occurred. Helen Richards, an experienced Victorian terrestrial orchid grower, shared in an email how she grows them.

Cryptostylis species grow from brittle rhizomes which can be quite long and they resent frequent disturbance. Mine are potted into a pot therefore that is large enough for the long roots and which will accommodate further growth for several years. My mix is ANOS basic mix, the same as I use for Pterostylis and many other genera. They need to be kept moist all year round, especially in summer when they flower and new leaves appear, their active growing period. I grow them in an area of moderate light. Others have seen pollinators active on the flowers but I haven’t. However seed capsules frequently develop without my assistance with a toothpick. Richard Thomson says they haven’t had success germinating the seed.”

Reference

https://nossa.org.au/2017/03/03/upside-upsisdedown/

http://bie.ala.org.au/species/http://id.biodiversity.org.au/name/apni/89052

http://saseedbank.com.au/species_information.php?rid=1288

Personal communications Helen Richards (OAM), Chairman Australian Orchid Foundation

Bates, R. J., ed. (2011). South Australian Native Orchids. Electronic version, 2011. NOSSA

The other entries :

1702 sm RWL Spiranthes alticola

1702 sm RAL Pterostylis falcata

1702 sm PM Thelymitra villosa

Q&A: How do I deal with mould in my orchid flasks?

Question:

I have recently been learning about propagating orchid via flasks but I have mould in some of the flasks.

Orchid Seeds in flask with mould

Flask with orchid seeds and mould

There is mould in the flask with orchid seeds and also in the flask with Diuris tricolour in bulbs.  The bulbs are almost ready for deflasking.

Diuris tricolour in flask

Flask of Diuris tricolour (no mould) – these will be deflasked later this year.

 

What can I do?

Answer:

With a home laboratory, no matter how careful one is, mould can still contaminate the jars of agar. If mould occurs when the orchids are still in seed, then the whole jar needs to be discarded.  The seeds will not survive.

With the Diuris flask, as they are almost ready for deflasking, pot them out straight away. This needs to be done within 10 days of the mould appearing. The weather (March, 2017, South Australia) is still a little too warm but if left in the flask, the plants will die.  Potting them out may give them a chance of survival.

When deflasking, it is important to rinse all the agar off the bulbs before potting on as normal. Once potted, it could help to cover the pot with a cut down clear drink bottle with the lid removed. This will allow some air to circulate. Keep the pot in a shady spot.

Diuris tricolour in pot with bottle top cover

Potted Diuris tricolour with protecting bottle cover

Will it survive in the pot? Hopefully it might but at least the plants have a better chance of survival then if left in the flask where it would surely die.