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.
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.
There are many different activities involved with orchid conservation. In situ conservation consists of looking after the orchids where they are growing; maintaining and protection of habitats and ecological systems. On the other hand ex situ conservation is caring for the orchids in cultivation in a similar way that zoos maintain an animals species that is extinct in the wild.
For the orchids one form of ex situ conservation is via seed collection and the propagation of new plants. With many of our terrestrial orchids this is not an easy task but here in South Australia an attempt is being made with four of our endangered orchids.
Unlike some of our terrestrial orchids these are ones which we have not been able to grow. There is a collaborative effort co-ordinated through the South Australian Seed Conservation Centre (Seedbank) to change this. Amongst the people helping the Seedbank are members of the Native Orchid Society of South Australia, students from Kildare College and Dr Noushka Reiter of the Royal Botanic Gardens Melbourne.
On July 30 2016, Dan Duval of the Seedbank was interviewed by Jon Lamb on Ashley Walsh’s ABC 891 Adelaide Talkback Gardening program. It is an informative interview and well worth the listen.
For more information on the work of the Seedbank, visit their website
Video as heard on Talkback Gardening with Jon Lamb and Ashley Walsh – Saturdays from 8.30 on 891 ABC Adelaide.
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.
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.
[Primary source material is the NOSSA Journals. Direct quotes from the Journal in blue and additional information in black.]
Sometimes gleanings take much time and effort to locate but other times there is an abundance of information just waiting to be picked up. This was the case when searching the Journal for information on Harold Goldsack.
Upon the death of Dr R S Rogers, Harold Goldsack became the leading authority of South Australian orchids. To quote Peter Hornsby (1977), NOSSA’s first editor, “Harold is undoubtedly the most experienced of our native orchid botanists and knows more of the history of our orchids than anyone alive.”
Though not a foundational member, Harold was one of NOSSA’s early members, joining at the end of 1977. He was both a grower of epiphytes – winning the Champion epiphyte for 1982 (Dendrobium x gracillimum) and terrestrials – producing the first greenhood hybrid, Pterostylis Cutie (baptistii x cucullata) which was registered on 5th March, 1982. At the meetings he gave talks, plant commentaries and judged the orchids. Outside of the meetings he was active in advancing the cause of Australian orchids. His enthusiasm influenced many people, one person being a young Mark Clements, current Research Scientist, Centre for Australian National Biodiversity Research, CSIRO, Canberra.
It is not surprising than that in 1984 he was made NOSSA’s second life member.
Bob Bates wrote an informative biography in Harold’s obituary.
Journal 1989 Volume 13 No 4 May
Vale Harold Goldsack.
It is with sadness that we announce the passing of life member Harold Goldsack on April 25th. Our sympathies to his family.
Harold was born in East Bengal, India on 27th June 1908. He once told how he could remember epiphytic orchids blooming outside the bedroom window of his childhood home.
His family moved to Adelaide in 1916 and he attended Princes College as a boarding student.
He was introduced to South Australian orchids in bushland adjacent his family’s orchard at Coromandel Valley using Rogers “Introduction to the Study of South Australian Orchids” to identify these. Harold in 1924 introduced himself to Dr Rogers and they became good friends. Harold soon began to find orchids that were new to Dr Rogers and this fired his enthusiasm so that he began a serious study of our orchid flora.
One day in 1928 on a visit to Dr Rogers, Harold was shown the very first collection of the underground orchid Rhizanthella gardeneri. This was to be the subject of the last article Harold wrote over 50 years later.
With the passing of Dr Rogers in 1942 Harold became the foremost authority on South Australian orchids corresponding regularly with H M R Rupp, W H Nicholls and A W Dockrill. His extensive collection of pressed orchids was donated to the State Herbarium in 1978.
Harold wrote many articles on orchids his best known being “Common Orchids of South Australia” which appeared in the S Aust Naturalist in June 1944 and was used in “National Parks and Wild Life Reserves” book from 1965-1970. Harold also revised the orchid section of Black’s “Flora S Australia” in 1943.
Besides drawing and photographing the S Aust orchids Harold developed a large personal Orchid Library and cultivated many Australian orchids which he displayed at shows including our NOSSA shows. The first registered Pterostylis hybrid Ptst. Cutie was made by Harold and the name given to the original clone now grown by hundreds of orchid lovers is “Harolds Pride!”
His main interest was to enthuse others to see the beauty and value of our native orchids through his articles and the many illustrated talks he gave to natural history groups.
Harold was a member of the Royal Society of S Australia.
He was a Foundation Member of the Australian Native Orchid Society. (ANOS)
Ever ready for a challenge Harold at age 64 began studying for his Engineering and Surveying Certificate gaining distinctions in Maths, then working on the surveying of the S E Freeway.
Harold Goldsack’s name is commemorated in the South Australian endemic orchid Prasophyllum goldsackii, a fitting tribute to a true orchid lover.
R Bates
Prasophyllum goldsackii – Photographer Ken Bayley
Bibliography of Papers by Harold Goldsack
Orchids of Coromandel Valley – SA Naturalist XIV, Nov 1932 PP 12 – 15
Notes on Caladenia Catifolia – R Br SA Naturalist XV, March 1934, pp 59 – 63
National Park of South Australia – Field Naturalists Sect. of Royal Soc of SA 1936, Being Vol XVII, Nos 1 to 4 of SA Naturalist pp 52 – 54 Orchids
Common Orchids of South Australia – SA Naturalist XXII June 1944 PP 1 – 12 with line drawings of 52 species
New Orchid Records for South Australia – SA Naturalist XXII June 1944, p 13
National Park and Reserves – Commissioners of the National Park, Sept 1956 pp 59 – 79 with line drawings of 52 species of Orchids, p 195 Distribution and flowering times of orchids in the National Park and Reserves
SA National Parks and Wild Life Reserves – Commissioners of the National Park and Wild Life Reserves, March 1964, pp 46 – 64 Orchids with line drawings of 52 species, pp 189 – 199. Distribution and Flowering times of Orchids in the National Park and Reserves
Orchids of the National Park and Wild Life Reserves – Reprinted 1965 by Field Naturalists Society, if (sic) SA from “SA National Parks and Wild Life Reserves” with permission of the Commissioners of the National Park and Wild Life Reserves
Blacks’ Flora of South Australia – Revised edition of p1, 1946 Assisted Rev H M R Rupp and W H Nicholls with the revision of the Orchidacea
Pollination of Caladenia deformis R Br – R S Rogers transactions of Royal Society of SA Volume LV Oct 1931 The pollination of Caladenia deformis as observed by H G was written up by Dr R S Rogers in an article for the Royal Society of SA
Rhizanthella gardnerii R S Rogers – The Orchadian p 113 Sept 1979 A note about the discovery of this orchid
Following is the article by Harold Goldsack referred to by Bob Bates in Harold’s obituary. Though he wrote for other publications, this was appears to be the only one in the NOSSA Journals.
Journal 1979 Volume 3 No 8 August
RHIZANTHELLA GARDNERI Rogers Harold Goldsack
Corrigin, Shackleton, Goomalling, Munglingup. Western Australia.
A new locality where the subterranean orchid Rhizanthelle gardneri Rogers has been found, as noted by Don Voigt in his letter to Roy Hargreaves to brings with it hope that after 50 years the secret life of the remarkable orchid may be unveiled. It also brings back memories of my first encounter with this plant.
As a young orchid enthusiast I had been collecting for, and writing to, Dr R.S. Rogers of Adelaide, who, at that time, was an extremely busy public personality. To my surprise, one day in 1928 I received a note from Dr Rogers inviting me to call at his house in Hutt Street after surgery hours as he had something to show me which he was sure would be of interest.
Naturally, I took the first opportunity to visit the Doctor, whereon he brought into the room a large jar with some white vegetable pickled in it. With a smile he said “Have you ever seen anything like this before?”
Well, there it was – this unique subterranean orchid from Corrigin, Western Australia, sent over by Mr C A Gardiner, the Government Botanist of Perth, who had realised the importance of this discovery.
The first plants were found in an area of virgin lane that had been rolled, burnt and then ploughed, which operation uncovered the white underground rhizomes. Mr John Trott, the discoverer, was puzzled by this strange plant growing around the stumps of Melaleucauncinata R Br, common in the area, and sent it to Mr C A Gardiner. He, realizing the orchidaceous nature of the plant, visited the area, made personal observations and then sent a specimen to Dr Rogers for study, which led to the description of a now sub-tribe, genus and species of orchid – Rhizanthella gardneri Rogers.
Soon after this the Field Naturalists Society were to hold their Wild Flower Show in the Adelaide Town hall and attempted to have this unique specimen displayed there. However, the plant was too valuable to risk and an artist – Mr Lyall Lush – made a black and white drawings which was exhibited instead.
Within three years, on the east coast of Australia at Bulahdelah, another subterranean orchid Cryptanthemis slateri Rupp was unearthed. Unearthed is the word, for this one was unearthed by Mr Slater who was digging up rhizomes of Dipodium punctatum, the “Wild Hyacinth”, to attempt to grow them. All plants of the new orchid were found growing in association Dipodium. The importance of this find was such that Rev H I R Rupp was given a grant to travel to Bulahdelah to make further studies. This second find aroused worldwide interest and a German botanist suggested that the flowers of Cryptanthemis slateri were underground spikes of Dipodium. The morphology of the flowers soon disproved that theory.
Regarding this orchid, which Rupp named in 1932, Dr Rogers commented to me that he was sure that Rev Rupp’s parishioners must have had a very brief sermon the week Rupp received the first specimen of Cryptanthemis!
Dr Rogers then lamented that the orchid hunter has to add a plough and a pick to his orchid collecting equipment!!
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. 10, November, 1983 GROWING EPIPHYTIC ORCHIDS IN SOUTH AUSTRALIA – R.T. Robjohns Sarcochilus hartmanii (Hartman’s Sarcochilus) This has a range from the Hastings River in north-eastern New South Wales to the McPherson Ranges in southern Queensland, although some authorities extend this to the Atherton Tablelands in northern Queensland. S. hartmanii is lithophytic and is normally found growing on rocks, sometimes forming large masses but usually in small clumps, however, it occasionally grows on trees. It varies in its habitat from bright sunny positions on cliff faces, above 600 metres, to shady seepages. It must be remembered, however, that this is an area of high summer rainfall and in late summer and autumn has considerable cloud cover with accompanying high humidity.
The leaves, 4 to 9 per stem, from 10 to 20cm long, 1 to 2cm across, are thick, fleshy, deeply channelled and slightly twisted at the base.
Racemes are 6 to 25cm long with 5 to 25 flowers usually sparse at first then crowded towards the apex. The flowers are 2 to 3cm in diameter and have petals and sepals of glistening pure white with deep maroon or crimson spots near the base, though sometimes all white.
The flowering period is September to November.
In 1979 a clone of Sarcochilus hartmanii “Kerrie” was awarded AM/AOC. It was a large plant with 16 spikes and approximately 320 flowers measuring 31mm across the petals.
It adapts well to cultivation and is not difficult to grow, doing well in a shadehouse with 60-70% shade and a good air circulation. I have it growing and flowering in a plastic pot in a bark, charcoal* and polystyrene foam mix and would suggest underpotting rather than overpotting. Good drainage is essential. Other growers recommend shallow baskets or rafts about 8 mm of stag-horn fern fibre as this allows the plant to spread more naturally. It likes to be kept moist (not wet), prefers a humid atmosphere and does not object to regular year-round (½ strength) doses of foliar fertiliser.
The following article written by Robert and Rosalie Lawrence is from the Volume 37 No 9 October 2013 Journal of the Native Orchid Society of South Australia
Orchids and the concrete jungle that makes up a city don’t seem together, particularly the terrestrial orchids. Yet in the heart of one of the world’s most well known capital cities such an orchid was found. On the 19th July 2013, the Telegraph reported that botanists from the Natural History Museum had found in the middle of London a white helleborine orchid (Cephalanthera damasonium) which had not been seen in that region since 1900. It was found in the Queen’s backyard, Buckingham Palace. Despite the building, demolishing, rebuilding, bombing and rebuilding that has been going on for the last 400 years, here is an orchid which has survived to surprise the botanist. (For details see Long Lost orchid found in Buckingham Palace Garden)
It is always heartening to hear good news about orchids but here in Adelaide we have our own encouraging story. Settlement in Adelaide is not as long as in London by a long shot but in our own short time we have managed to clear and cover some very good land with concrete and bitumen. The result has been that much of our native flora has been lost with many of our orchid species being the first to disappear.
In recent years effort has been made to bring back the bush with revegetation projects. This work has not tended to involve the orchids, the work of Heather Whiting and her team of volunteers at Vale Park being an exception. Consequently, any orchids found on such sites tend to be the more robust species principally Pterostylis pedunculata, Microtis sp. and in some cases Linguella sp.
Finding anything else will always be special; but that is what has happened at site where a Shell petrol station stood for decades on the corner of Portrush and Greenhill Roads. After the demolition of the service station the site was an area of bare clay for about a decade. Then in 2003, work began on restoring native vegetation incorporating a mini wetland in an area of 2,000 square metres that was given the name Linden “Bush Garden”. Indigenous flora was sourced from the local region and the site has been kept meticulously weed-free by dedicated workers.
Originally 60 local species were planted with several other species arriving by themselves. Among the latter group are five species of orchids. These include a Microtis species and Pterostylis pedunculata, but the other three are more surprizing – Arachnorchis tentaculata, a small blue-flowered Thelymitra species and a Caladenia (syn Petalochilus) species. How they came to be there is a mystery. The long term viability of them will depend upon the continued maintenance of this unique site.
The City of Burnside should be congratulated both for its foresight and initiative as well as its ongoing support of this project.
Natural regeneration at Linden Gardens includes three plants of Arachnorchis tentaculata (King spider Orchid) that are understood to have flowered for the first time this year (2013). The buildings of the council chambers can be seen in the background.
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. 9, October, 1983
GROWING EPIPHYTIC ORCHIDS IN SOUTH AUSTRALIA – R.T. Robjohns
Dendrobium aemulum (Iron Bark Orchid)
There are several growth forms of this orchid due probably to the wide variety of habitats, the flowers of all forms being similar. It has a range from the Clyde River in south eastern New South Wales to the Atherton Tablelands in Queensland
Those growing in the rainforests of New South Wales and Queensland have straight stems up to 20 cm long with 2-4 shining dark green leaves. On the edge of the rainforests in northern New South Wales and southern Queensland in the dense brush forest, the principal hosts are the trunks of “Brush Box” trees where it has stems up to 30 cm long which tend to radiate from a central point. It also has 2-4 dark green leaves. In the open forest areas its hosts are the “Iron Bark” eucalyptus trees, it has shorter (up to 7 cm), stouter (up to) 1 cm), and more crowded stems, sometimes growing into large mats and having 2-4 yellowish green leaves. On the Atherton Tablelands at an altitude of around 750 metres and with callitris trees as its favoured host, it has very slender stems of about 0.3 cm with usually only two dark green leaves.
The flowering period is August/September. One to three slender racemes (5-10 cm long) occur terminally from between the leaves or at nodes along the stem, each raceme bearing 3-20 cm diameter. The flowers are usually pure white (sometimes pale cream) with purple markings on the labellum, the whole raceme turning deep pink before withering.
This is another of our natives which to date does not appear to have attracted much attention from the hybridisers. “Emmy” aemulum x kingianum seems to be the only registered cross.
I find D. aemulum is an easily cultivated and highly rewarding plant that flowers freely with masses of feathery flowers. It grows well mounted on hardwood slabs, cork or on a paperbark branch under 50% shadecloth. Mine get about 65% shade in mid-summer and receive an occasional spray of weak foliar fertiliser during the growing period.
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. 8, September, 1983 GROWING EPIPHYTIC ORCHIDS IN SOUTH AUSTRALIA – R.T. Robjohns Dendrobium gracilicaule D. gracilicaule is found from Kiama in eastern New South Wales to the Bloomfield River in the south east of Cape York Peninsula in Queensland. It has one of the widest ranges of habitat of any of our epiphytic orchids, growing in the light coastal scrubs, the dense rainforests and, in the tropical areas, on the tablelands. With such a variation in altitude (from near sea-level to about 1200 metres) it follows that there is a wide variety of hosts, even occasionally growing as a lithophyte on rocks. The stems are long, thin and cylindrical, ½ to 1 cm thick, and from 20 to 60 cm in length with 3 to 6 ovate to lanceolate, terminal leaves, 5 to 13 cm long and of rather thin, leathery texture. The racemes are short (5 to 12 cm) and bear 5 to 14 small, cup-shaped flowers of a dull or light yellow colour having the outer sepals lightly to heavily blotched or spotted with a brown or red-brown. Occasionally they are found a brighter yellow and without blotching. The flowering season is from July to September. D. gracilicaule must surely be one of the hardiest and easily cultivated of our Australian epiphytic orchid species as it is adaptable to almost any conditions. I have it growing and flowering on hardwood slabs, paperbark limbs and in a pot, but I think it is better if mounted. It receives 50% – 60% shade and occasional foliar fertiliser. I protect it from frost but the cold does not affect it. It does not flower from first year stems but will flower from mature stems for several years, even after they are leafless. Although most racemes are terminal or near, I have had racemes occurring from nodes halfway along a leafless canes. There are two natural hybrids, i.e. D. x suffusum and D. x gracillimum. D. x gracillimum is a natural hybrid between D. gracilicaule and D. speciosum in which the features of D. gracilicaule are dominant in the flower while in D. x suffusum, the natural hybrid between D. gracilicaule and D. kingianum, D. kingianum is the dominant parent. D. gracilicaule has not attracted professional hybridists, probably because the flowers are not as outstanding as many of our other epiphytes, only two crosses appear to be registered: D. Susan (D. gracilicaule x D. falcorostrum) and D. Shan Leaney (D. gracilicaule x D. gracillimum).
With the development of cities here in Australia, many of our orchids were lost as habitat was cleared and the newly arrived settlers built houses and reconstructed the gardens they knew from the Old World; but the odd pocket of native bushland has survived. Cemeteries and golf courses have often been the only refuge for remnant bushland. One such refuge has been The Pinery, Grange Golf Club, the only known location of Oligochaetochilus arenicola (syn. Pterostylis arenicola) on the Adelaide Plains. In the National Parks and Wildlife Act, this orchid is scheduled as vulnerable. The Golf Club left this site intact and has been supportive of the conservation efforts of the Threatened Plant Action Group who in turn have received assistance from the Native Orchid Society of SA and the Natural Resources Adelaide and Mt Lofty Ranges.
Typical of the rufushoods, this Oligochaetochilus arenicola shows the sencesing leaves, pendent petals and hairs on the labellum. Photographer: H Lawrence
Below is a media release from the Natural Resources, Adelaide and Mt Lofty Ranges
Orchids come in ‘under par’ at Grange Golf course
News release
30 September 2015
A tiny remnant population of rare orchids which survives in a patch of bush on Grange Golf Course has increased 50% since last year, according to a new survey.
The survey conducted this month found 1200 individuals of the Sandhill Greenhood Orchid (Pterostyllis arenicola), a nationally threatened species which is considered critically endangered in the Adelaide and Mt Lofty Ranges region.
When surveys began 20 years ago, only about 100 plants survived at this site. But the latest survey has revealed the population is steadily increasing
The orchid comeback is thanks to decades of care by four groups involved with the annual survey: the Threatened Plant Action Group, the Native Orchid Society of SA, Natural Resources Adelaide and Mt Lofty Ranges, and with support from the Grange Golf Club.
The tiny fragment of native pine bushland in the middle of Grange Golf Course is one of the only known locations of this species within the entire Adelaide and Mt Lofty Ranges region, with other small populations known from near Wellington and Tailem Bend.
The orchid grows 10cm-25 cm high and produces hood-shaped flowers that are green and brown or red-brown with white markings. Most species of orchid flower for only a short period and for the Sandhill Greenhood, it will flower only for the next few weeks.
Grange Golf Course just happens to provide ideal conditions for the plant: red sandy soils and an over-story of native cypress pine trees.
Dedicated project partners have tackled the main threat to orchids – suffocation by Perennial Veldt Grass and Soursob weeds – through years of patient hand weeding.
The orchid comeback is a great success story of collaboration across the community to save one of our state’s tiny floral gems.
As a demonstration of nature’s interdependence, conserving the Sandhill Greenhood also means conserving a particular mycorrhizal fungus that must be in the soil for Sandhill Greenhood seeds to germinate. In addition, the flowers must be pollinated by a particular type of insect, the fungus gnat. The gnat is attracted by the orchid’s pheromones and tries to mate with the flower, only to find itself loaded up with a packet of pollen which it then transfers to the next flower as it continues its romantic adventures.
While the survey results are good news, the Sandhill Greenhood population is still precariously small, and it is hoped that as the population grows, so do the options to secure the species into the future.
South Australia has over 260 species of orchids, including 50 species of greenhood.
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. 7, August, 1983
GROWING EPIPHYTIC ORCHIDS IN SOUTH AUSTRALIA – R.T. Robjohns
Dendrobium pugioniforme (Dagger Orchid)
This is an epiphyte frequently growing into large pendulous masses on the branches or trunks of trees, mainly in the rain forest areas from Mt. Dromedary on the south coast of New South Wales northwards to the Bunyah Mountains in south eastern Queensland. The stems are slender, wiry and branching, often quite long and usually tangled. Thin creeping roots develop freely from nodes at the branches.
The distinguishing feature of the numerous shiny, thick flat, ovate to lanceolate leaves is the sharply pointed tip.
The flowers are usually single but sometimes 2 or 3 per inflorescence and are 2 to 2½ cm in diameter. The petals and sepals are light green, the labellum pale with bright red or purple markings. The flowering season is September to November.
It is a reasonably hardy plant which will respond to cultivation on quite a variety of hosts. I have had success using Melaleuca, and find that it responds to a position having plenty of shade and moisture, particularly during our summer. Although in the wild it will tolerate cold conditions, (being found from near sea level to around 1300 metres), it will require shelter from our winter frosts
Most authorities designate it an epiphyte, however, in “The Orchadian” Vol. 4, No. 2, p. 24 (1972) D.L. Jones reports having found a bleached and tough looking plant growing on Alum Mountain with its roots amongst leaf litter in a crevice. Again in “The Orchadian” Vol. 7, No. 7, p. 164 (1983) G. Walsh describes ‘inter alia‘ lithophytic forms of D. pugioniforme growing in the Illawarra District of New South Wales.
In view of this it could possibly be grown in a pot, but as it grows quite readily on a slab I have felt it pointless to possibly waste a plant just to grow it in a pot. Fertilise in the growing season with foliar fertiliser at half the recommended strength.
Two naturally occurring hybrids of D. pugioniforme have been recorded – D. pugioniforme x D. tenuissimum and D. pugioniforme x D. beckleri but they are relatively rare (Ford, “The Orchadian”, Vol, 3, No. 7, p.88: Dockerill, Aust. Indig. Orch. Vol. 1, pp 370-371) and as yet it has not yet attracted the hybridists as there does not appear to be any registered crossings.
NOSSA 