Mad dogs and Englishmen are not the only ones to go out in the midday sun. For orchidologists to see Sun Orchids flowering, then it is out into the midday sun on a hot day because that is when they open. There is no point going much before 11am and by 2pm most are closing and no point going out on a cool or windy day.
But for those who don’t want to go out (or cannot get out) into the midday sun, here is a video to be viewed in the cool of the shade.
This video features the Leopard Sun Orchid (Thelymitra benthamiana) an uncommon Sun Orchid in South Australia. Unlike many sun orchids which requires a view of the flower to confirm identification, this one can be identified by the leaf alone. At the beginning of the video take note of its distinctive leaf.
Spring is here and it was reflected in the variety and large number of entries. Lorraine Badger and Ros Miller entered Western Australian species – Caladenia x ericksoniae (Prisoner Orchid) and Paracaelana nigrita (Flying Duck Orchid) respectively. The other six entries were all from South Australia, Diplodium robustum (Common Green Shell Orchid), Caleana major (Flying Duck Orchid) both from Jane Higgs, Greg Sara’s Oligochaetochilus sp (Rufoushood), Judy Sara’s Arachnorchis leptochila (Queen Spider Orchid), Claire Chesson’s Diuris behrii (Cowslip Orchid or Golden Moths) and the outstanding winning picture Pterostylis cucullata by Bevin Scholz.
In many ways, Bevin’s picture of P. cucullata (Leafy Greenhood) is a special picture because it represents some of the conservation work with which NOSSA is involved. For many years NOSSA has worked with the Threatened Plant Action Group (TPAG) to weed the areas in Belair where this species is located and to see such a good show of plants is encouraging. It is a tribute to all who have contributed with their time and labour.
P. cucullata is rated Vulnerable both in South Australia and Victoria, and Endangered in Tasmania. It is also rated Vulnerable under the EPBC Act (Federal). Nationally it is known from about 110 sites with most of these sites being in Victoria and only a few sites in South Australia with Belair National Park having the largest and most important population for the state.
Historically this species covered an area of 2107 km2 in the Lofty Block region but that has now contracted by 82% to only 366 km2 with few locations. With such a reduced range, recovery plans were developed, both at state and federal level. The plans examined the risks and threats to the survival of the different populations.
One of the threats to this orchid is fire, including proscribed burns. Unlike some species such as Pyrorchis nigricans, Leptoceras menziesii or Prasophyllum elatum which flower well after fire, P. cucullata is fire sensitive; populations decline substantially. There does not seem to be a safe time to burn for this species. Should a population survive a burn, it would take it many years to recover.
Fire also leaves the population vulnerable to another threat, that of weed invasion. Unfortunately, it is weedy where this species survives but over the years, a consistent, targeted weeding program has resulted in a declining weed population. NOSSA and TPAG have appreciated the work and effort of volunteers and gladly welcome anyone else who would like to join. And one of the rewards? A beautiful, sunlit display of flowers as seen in Bevin’s picture.
Epiphytic orchids grow on trees or rocks (lithophytic), where they are dependent on their host for support but not for food.
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.
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
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.
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.
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.
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 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.
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.
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.
If you are out and about this week, keep an eye out for this attractive and unusual greenhood with its bottle brush labellum and rosette of “pineapple” like leaves.
Commonly known as Woodland Plumed or Bearded Greenhood, or Plumatochilos sp. Woodland Bearded Greenhood. The reason for the phrase name is because many consider that it is a separate species, in this instance, from Plumatochilos plumosum (syn Pterostylis plumosa). Originally all of the Bearded Greenhood were considered as one species – Pterostylis barbata but then Leo Cady named Pterostylis plumosa as a separate species. David Jones in his 2006 tome listed four species, P. barbatum, P plumosum, P. tasmanicum and P. turfosum.
Here in South Australia, Bates lists P. tasmanicum and two with phrase names suggesting that they are distinct from P. plumosum.
Peter Fehre recently posted on the Tasmanian Native Orchids Facebook page some helpful hints differentiating between P. tasmanicum and P. plumosum. Very similar information is found in Bates South Australia’s Native Orchids. These differences are:
P. tasmanicum – a short plant: short flower stem (not more than 14 cms), short labellum (to 15mm) , short ovary; short blunted galea (hood) to 25mm. It prefers damp, sandy areas and swamp margins.
P. plumosum – has length; long flower stem (10 – 30 cm), galea to 40mm with a long tip, long labellum (to 25mm). It is a plant of the woodlands and forests growing on well drained soil.
The differences between the two phrase named species are more subtle
R J Bates, 2011, South Australia’s Native Orchids DVD, NOSSA
D L Jones , 2006, A Complete Guide to Native Orchids of Australia
The Native Orchid Society of South Australia (NOSSA) is affiliated with the national body of native orchid society, Australian Native Orchid Society (ANOS). NOSSA regularly sends reports of its to ANOS. This year’s report covered four years of the society’s activities and is reproduced here to give readers an idea of the many things that we do. This report was produced by Robert Lawrence (currently Vice President).
NOSSA REPORT 2012 to 2016
I believe that the last annual report from the Native Orchid Society of South Australia was in 2011 when we were just commencing a three-year plan with the establishment of a series of subcommittees. All of the committees have since ceased to exist, but not without significant accomplishments.
The Website Subcommittee had established a website, but a Webmaster has since been appointed. The website now uses WordPress and is maintained so that its management could easily be transferred to another person. The website provides a weekly educational post about Australian orchids. It has also provided a point of contact from those outside of the Society. It is linked to a Facebook page that increases the profile of NOSSA among those interested in orchids throughout Australia and beyond.
The Education Subcommittee had established a picture competition at the monthly general meetings. There is still only a small number of contributors, but many excellent pictures are shared. The winning picture from each meeting is used as a basis of one of the weekly posts on the website.
The Education Subcommittee had a vision to produce a brochure of 20 common orchids of the Adelaide region for free distribution to the general public. The NRM (Natural Resources Management) Education ran with the idea and produced a poster of Common native orchids of the Adelaide Hills. This provided brief, but comprehensive, profiles of 29 native orchids and the weedy species. This has been printed as a double-sided poster and is available from the website of Natural Resources Adelaide and Mt Lofty Ranges. NOSSA members worked with NRM staff on the details of the poster and NOSSA members contributed many of the photographs. This poster was completed and launched in April 2015.
NOSSA also provided monetary assistance as a loan with the publication of the field guide entitled, Start with the leaves. A field guide to common orchids and lilies of the Adelaide Hills. This guide covered 50 orchid species as well as native lilies and some weeds in the Iridaceae family that are sometimes mistaken as orchids. The contribution of $8,000 was recovered only 8 months after publication.
The Disc Publication Sub-editing Subcommittee saw the publication of South Australia’s Native Orchids on DVD discs in time for the Spring Show in September 2011. Both the DVD and the book were published in time for the Spring Show in September 2011. Both continue to sell.
A new subcommittee has been established in February 2016 to oversee the publication of a field guide, expected to be called Wild Orchids of South Australia. It is proving to be a challenge to be brief enough to reduce the information to a size suitable for a field guide. (Editor’s note: it has since been decided to defer this until after the development of the interactive website, see below.)
NOSSA members have being working since 2014 to establish an interactive website and database modelled on the Go Botany website run by the New England Wild Flower Society in the USA. This was supported by a grant from the Australian Orchid Foundation. The project is called Wild Orchid Watch. It is hoped to produce an interactive, web-based orchid identification tool. Recording sightings through such means as apps on mobile telephones are also being investigated.
In 2014 NOSSA made a donation to help establish the Orchid Conservation Program. This was led by Dr Noushka Reiter. Once established, staff in the Department for Environment, Water and Natural Resources began to organise a trial with four threatened orchid species from South Australia. Noushka visited South Australia during 2015 and collected samples from each of these species and isolated fungi from these. Seed was also collected and work on propagation commenced in 2015. During 2016 NOSSA sponsored the propagation of one of the four species through the Adelaide Botanic Gardens. Caladenia gladiolata, an endemic species, was selected.
Paul Beltrame, a secondary teacher at Kildare College, contacted and joined NOSSA during 2014 with the interest in getting girls at this school involved in the propagation of native orchids. A program was organised modelled in the Orchids in Schools program run by the Orchid Club of South Australia with Les Nesbitt’s involvement.
A delegation from Kildare College, ably assisted by their enthusiastic laboratory assistant Nenah McKenzie, visited Noushka in Melbourne and learnt the technique for separating and growing fungi. They have since separated fungi from two of our more common greenhood species and supplied this for seed kits that were made available to members as a trial at the start of the 2016 growing season.
The trial of seed kits was done for Pterostylis nana and Pterostylis sanguinea. A trial was conducted in this growing season of seed kits for members. Kits included a pot, growing media, seed, fungus, mulch and instructions. There seems to be limited success with the current round, but improvements are planned from the lessons learnt. One particular growing mix proved successful with a small number of seedlings appearing. The contribution of the Orchids in Schools program at Kildare College has been necessary for the isolation and production of fungi for the kits.
In October 2012 Cathy Houston and Robert Lawrence collected seed of Pterostylis arenicola from the only population on the Adelaide plains after monitoring in September indicated a good year for seed production. The seed was germinated in 2013 and was deflasked at a working bee at the Adelaide Botanic Gardens in early August 2016. The students from the Orchids in Schools program at Kildare College participated. Latest reports are that 40 plants look like surviving. These will be used for seed production and for reintroduction.
In 2012 NOSSA was asked to care for and propagate rescued Diuris behrii plants from Hillgrove Resources Mining Lease near Kanmantoo in the Mt. Lofty Ranges. The plan was to maintain the rescued orchid clones in cultivation for several years and to produce additional plants for reintroduction within the mining lease area each Autumn. A comprehensive recording and auditing system has been put in place to track each clone and any seed/daughter tubers/plants. By August 2015 there were 609 plants with 75 original mother plants. There were 95 daughter plants returned to the site for revegetation in each of the years 2014, 2015 and 2016, a total of 285 plants.
Funding from Hillgrove Resources has assisted NOSSA financially and has made it possible to consider funding conservation work. NOSSA is planning to apply for charity status so that donations can be used for tax deductions. Donations will then be feasible through our website. We are also starting an orchid seed bank. Seed will be available only to members and it is hoped that this will increase our membership. There is a demand for Australian orchids overseas and it is hoped that this will become a means for raising funds for conservation. Other means of fund-raising such as sausage sizzles and selling kits for craftwork are also being considered.
NOSSA members still continue to be involved in surveys and monitoring threatened orchids. Members have been involved in the planning of monitoring.
The management committee of NOSSA is currently working on a revision to the Rules of Association. In the current version there is a two-year limit on the term of the President of two years. In the first 16 years from 1977 there were there were eight different presidents before one had a second term. Bill Dear was president in alternate terms until he retired and moved to Western Australia in 2012. Robert Lawrence was elected president in March 2014, but for the first time in 2016 there were no nominations for president and he was nominated to the role of vice president with no other nominations. The management committee has appointed a subcommittee to review the Rules in relation to the terms of the president. Another change planned is change from having monthly general meetings to having less formal monthly meetings at which no decisions are made or minutes kept. All resolutions will require calling a formal special meeting. This idea is adapted from the approach used by ANOS Victoria.
Over the last two years NOSSA has asked new and renewing members to complete a survey of their interests. This has proved to be an effective way of getting information on the interests of our members with 79 responses, this being about half of the number of memberships. This is an overall summary of the results ranked according to number of responses:
Area of interest
General Orchid Knowledge
At its establishment NOSSA was primarily a Society of orchid growers. These figures reflect a decline in interest in growing orchids. The figures are somewhat surprising in that the numbers interested in growing orchids are much larger than the number of growers. Presumably some of these are interested in learning with a view to getting involved with growing later. At least we hope this is the case.
We are certainly noticing a decline both in our numbers of growers and in members involved in surveys due to age and health.
The greatest number expressed an interest in general knowledge and we are relying on the Journal and the Website help to keep people interested and informed. Next was field trips, but we haven’t had that many that have attended field trips in in the last few years. Only 11 of those who expressed an interested in field trips are not interested in photography, the next item of interest, and only 10 people interested in photography were not interested in field trips. Not many of these share their photographs at monthly meetings. We are hoping to get members to make their photographs available for the identification guides.
It is pleasing that 58% are interested in conservation, thus supporting the efforts of our Conservation Officer.
Growing terrestrial orchids was next on the list; we hope that the tuber bank and the NOSSA Seed Kits are meeting the demand from members. Twenty-two of the 41 interested in growing orchids are interested in growing both terrestrial and epiphytic orchids. Only 8 of the respondents are bringing plants to meetings and a couple of others have not completed the survey. Of those interested in growing terrestrial orchids, one is a former grower and another is interested in growing them in situ at revegetation sites.
Thirty members expressed an interest in doing orchid surveys and three of these are interested in participating in the future, presumably when more time is available.
Citizen science is a new concept to many and came last in our list of interests. One who did not indicate an interest said he was monitoring orchids at a particular site; this has been taken as an interest. Surveys are certainly one form of citizen science and only 2 of those who indicated an interest in citizen science did not indicate an interest in being involved in surveys now or in the future. Thirteen of the 30 interested in surveys did not express an interest in citizen science. If these were included, interest in citizen science would be 43%.
Only seven members indicated an interest in all of the categories and one of these wants to keep in touch with the club and with old friends.
The Annual Spring Show in September 2015 was a particular success, largely due to the efforts of one our new members in promoting the show through local media and by other means. We also benefited from the donation of collections of growers who had decided not to continue with their collections.
NOSSA has continued to maintain a tuber bank that is available for members. A small number of our members are also members of ANOS Victoria, and have obtained tubers from their collection. This is hopefully contributing to the variety of terrestrial orchids grown by our members.
Working bees continued to be conducted in association with the Threatened Plant Action Group at Belair National Park for improving habitat for the nationally endangered Pterostylis cucullata (Leafy Greenhood), at Grange Golf Club to protect and monitor Pterostylis arenicola (Sandhill Greenhood) this being nationally vulnerable and locally endangered and on York Peninsula in conjunction with a local Friends group for the nationally endangered Caladenia intuta.
NOSSA has for many years used Australian Orchid Club (AOC) judges and knowledgeable members, who have all studied the ANOS judging rules, to judge orchids at NOSSA monthly meetings and shows. As the number of judges has fallen in recent years, judging training sessions have had to been discontinued. We wait in anticipation for a proposed ANOS judges correspondence course, as we have for more than 10 years. There are at least three AOC judges interested in the ANOS judging correspondence course. It is disappointing that ANOS Awards are still limited to Queensland, New South Wates and Victoria.
In summary, NOSSA continues to be active in many ways and these activities are working together to support each other.
Conservation of orchids takes many forms, one of which is weeding. NOSSA members often assist the Threaten Plant Action Group in this area. There are several sites where significant orchids are under threat from invasive weeds; and over the years, through consistent weeding, the weed front has been pushed back allowing the orchids an opportunity to recover and even increase in numbers. It is an ongoing task but seeing the orchids recover makes it an encouraging task BUT …
This activity is heavily reliant upon volunteers. And those who regularly volunteer deserve a big thank you from the community. BUT ….
More helpers are always needed. If you are interested in seeing the orchids, consider joining one of the weeding activities that are held throughout the year (these are advertised on this website). Often the weeding activities target a specific weed, so it is great for a beginner who does not have an in-depth knowledge of plants.
This month’s entries are an interesting collection as it is probably the first time that all entries are currently in flower. Rosalie Lawrence entered a Pterostylis pedunculata, Ricky Egel (second) Corysanthes despectans, Robert Lawrence (third) Pyrorchis nigricans whilst both Rob Soergel and Claire Chesson (winner) entered Pheladenia deformis. All four are colony forming species.
Both parts of the scientific name for the winning orchid refer to the labellum. Pheladenia meaning false glands which is referring to the calli and deformis meaning departing from the correct shape or mis-shapen.
The labellum plays an important role in pollination; it is the landing platform for the insect. Depending on the process by which the flower is pollinated – or at least attracting the pollinator – this can attempt to mate with the labellum which it has confused for a female of its species (pseudocopulation), or can then feed on the nectar produce. Like many orchids Pheladenia does not produce nectar so the actual attractant for the insect is hard to determine.
The labellum is a distinctive feature of orchids. A modified petal, they are so amazingly varied and complex that botanists often provided detailed descriptions of the features which are present in various combinations, as a means of describing the species. Terms such as lobes, margins, gland/calli, hairs/vestiture/setae, longitudinal ridges, plates, auricles, spurs, papillae etc are used to describe the various features of the labellum.
Some of the features of the labellum of P. deformis are:
It is stiffly attached to the column, unlike Arachnorchis tentaculata which is hinged and freely moving
It is tri-lobed meaning that the labellum shape is divided into three distinct sections.
Unlike Diuris pardina where this feature is easily seen, it is obscured as the outer two lobes are erect and curved in so that it forms a trumpet like appearance with the column.
The margins or edges of the labellum have fine teeth which are slightly curved inward. The margins of Arachnorchis cardiochila are smooth-edged and curve outward from the ‘throat’ of the labellum
It has two types of calli, fleshy, non-secreting glands.
The ones at the base are not as easily seen but they are described as being papillae, e., small, irregular, pimple-like projections or bumps.
The more obvious ones that give the flower its bearded appearance are elongate and without a swollen head, like the bristles on a brush.
In contrast, Thelymitra does not have any type of calli, although it should be noted that calli do play an important role in orchid pollination.
The apex, tip of the labellum, is curved under (recurved to reflexed)
To see some of the variety of labella, Orchids of South Australia (Bates and Weber, 1990) have several drawings detailing the differences on pages 35 to 38, 81, 97, 104 to 106, 114, 119 to 124.
So why spend time looking at details of labella?
It is not important for identifying Pheladenia deformis but it can be a distinguishing feature for other species, for example, the lateral lobes of Diuris maculata are much narrower than D. pardina (Jones, in Harden (ed.) 1993); or the shape of the callus cluster on Chiloglottis which alludes to the species.
Bates, R.J & Weber, J.Z. (1990) Orchids of South Australia, Government Printer, Adelaide
Brown, A., et al, (2013) Field Guide to the Orchids of Western Australia. Perth, WA: Simon Neville Publications
Jones DL (1993). Diuris in Harden GJ Flora of New South Wales, Volume 4. University of NSW Press, Sydney.
Jones, D L et al, (2006) Australian Orchid Genera, an information and orchid identification system, interactive CD-ROM
Thank you to Greg Steenbeeke for assistance with this article.
The following article is from Vol. 32 No 7 August 2008 Journal of the Native Orchid Society of South Australia Inc.
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 background. The 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.
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.
The following video is by Orchid Hunter, Julian Pitcher. Julian is concerned about the conservation of orchids and is also keen to teach others about Australia’s unique orchids. At the time of the visit, Julian was resident in Victoria; now he resides in Queensland. Enjoy an interstate visitor’s view of our beautiful orchids.
The second fact sheet in Terrestrial Culture notes is about Slow Multiplying Terrestrials.
FLAGBEARER SPECIES: Thelymitra nuda
Diuris, Pterostylis and Thelymitra. They are more expensive because they have to be raised from seed in flasks. SMs are not so easy because there is less room for error. A few have a near zero increase rate and will fade away unless additional plants can be produced to make up for occasional losses from predators and disease.
GROWTH HABIT: Australian ground orchids follow an annual growth cycle comprising 6 – 8 months as growing plants under cool (5 – 20°C max, 0 – 14°C min) moist conditions and 4 – 6 months as dormant tubers in hot dry (18 – 42°C max, 12 – 30°C min) conditions. The new tuber is produced in winter – spring. Each tuber sends up a shoot to the surface in Autumn and leaves grow rapidly in late Autumn/early Winter as temperatures fall and the rains set in. Pterostylis leaves are usually the first to appear in March/April followed by Diuris and Thelymitra in April/May. Sometime in October/November the leaves go yellow and then brown and dry as the days get longer, hotter and drier in late Spring.
LIGHT/SHADE:Australian terrestrial orchids are easy to grow. In Adelaide they thrive in a shadehouse of 50% shadecloth. Some species prefer heavy shade, others full sunlight, but most will adapt to a wide range of light intensity. Sun loving species (Diuris, Thelymitra & Rufa group Pterostylis) prefer a brighter location for good growth.
If the leaves and stems are weak and limp or if the leaf rosettes are drawn up to the light then the shading is too dense and the amount of light should be increased. The spring flowering species like higher light intensities at flowering time and flowers may have pale colours if placed in heavy shade, even temporarily, when flowers are just starting to open.
In very cold areas an unheated glasshouse may be required for frost protection although light frosts do not worry the majority of species.
AIR MOVEMENT/HUMIDITY:All species like good air movement and will not thrive in a stuffy humid atmosphere especially if temperatures are high.
WATERING:The soil should be kept moist at all times during active growth by watering gently if there is no rain. Hand watering is especially necessary in spring as soil in pots dries out more rapidly than in the garden. Watering must be done slowly so that the mat of needles on the surface of the pot is not disturbed. Slugs and snails love these plants and must be kept under control. Raising the pots off the ground on galvanised steel benching is very effective in controlling these pests.
After the leaves have turned yellow, let the pot dry out completely to dry up the old roots and tubers otherwise they may turn into a soggy mouldy mess and rot may destroy the adjacent new tubers.
POLLINATION/SEEDCOLLECTING:Flowering plants are hand pollinated and the seed collected just before the pods split open and the dust-like seed blows away. The seed is sprinkled on pots of mother plants at Easter or flasked.
REPOTTING:Repot every second year in half new mix. Repotting is normally done between November and January. The best results are obtained if the tubers are repotted in half fresh soil mix each second year. A suitable soil mix is 40% loam, 50% sand and 10% organic matter with a little blood and bone fertiliser added. A 5 mm sieve is a useful tool for separating tubers from soil. Replant the dormant tubers with the tops 20 mm deep. Cover the soil surface with a mulch of sheoak needles, chopped to 20 – 50 mm lengths, to prevent soil erosion & aerate under the leaves.
INCREASING PLANT NUMBERS:The pull-off-the-tuber method can be used with some diuris and Pterostylis species to double plant numbers annually. The pots can be knocked out and the tubers examined in Summer without harm.
SUMMER CARE: Keep the pots shaded and allow the pots to dry out between light waterings until mid-February when they should be set out in their growing positions and watered a little more often. The tubers of some species will rot if kept wet during the dormant period, others will produce plants prematurely which are then attacked by pests such as thrip and red spider and fungal diseases in the warm weather.
FERTILIZING:SMs will benefit from weak applications of folia feed in the early growth stages.