September Terrestrial Orchid Culture Notes

Continuing Les Nesbitt’s notes from the NOSSA Journal, this month he reminds us that not only is it a busy month but it is the month of the NOSSA Spring Show.

September is the busiest month of the year in the terrestrial house. apart from orchid shows every weekend there are numerous tasks to perform. The days are getting longer at a rapid rate. Day length increases by 2 hours in the 6 weeks from the 1st Deptember. Equinox is about the 21st September.

Early Spring weather is changeable from cold, windy & wet to warm & sunny. Give plants as much sun as possible as new tubers are developing rapidly. Hand watering may be necessary if there is no rain so get the hose out of winter storage. Do not let the post dry out this month. There are lots of flowers everywehere. Take photos as some flowers are fleeting and may only last one day. Different pollinators are about for the more colourful terrestrials that start flowering in spring.

Prepare your flowering plants for the NOSSA Spring Show. It is fun to put in a display even if you only have one or two plants. You learn a lot from other growers. We certainly need new exhibitors each year. Seek new species to add to your collection at the NOSSA Spring Show. Be there at 10am Saturday morning for the hard to get species which are always in short supply.

Spring is an ideal deflasking period but get it done in the first 2 weeks to give sufficient growing time to harden the plants and for tiny seedling tubers to form before the summer dormancy.

Notes on Tuber Removal

Start tuber removal after the middle of the month. In a wet year you may have to move pots under cover a week earlier to dry out a bit before knocking them out. working with mud is a real pain and not recommended. Use this method to propagate the slow multiplying terrestrials that are amenable. those recommended for slow multiplying are Diuris (punctata & behrii), and rufa group Pterostylis (cycnocephala & biseta).

Knock out the pot and carefully remove most of the soil from the plant. Find the new tuber which is usually whiter smoother than the old tuber. Hold the junction of the old tuber and plant stem firmly with one hand and grasp the new tuber with thumb & finger of the other hand. Twist & pull the new tuber which will separate from the plant. If the old tuber and leaves break apart you have stuffed up. Repot the plant & old tuber and water the pot. The new tuber can be buried in the same pot or potted up separately in another pot. Keep the plant watered for at least six weeks or as long as the leaves stay green. The plant may form one or two small new tubers before going dormant. In January you can repot and see how well the method worked.

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Monthly Terrestrial Orchid Culture – August

With Spring on the way, things are starting to change in the Orchid House. Here are Les Nesbitt’ notes from the August Journal 2019 Vol 43 No 7

Terrestrial Culture – August

The days are getting longer now, noticeably so after the middle of the month. When the clouds clear, the sun is stronger & higher in the sky. Temperatures increase and growth speeds up. Lots of buds are developing so there is plenty to see in the orchid house. The greenhoods are a feature with Pterostylis curta, nutans, pedunculata and their hybrids are all flowering.

Pests become more active. Look out for aphids on flower stems. Depending on the season deflasking can start after the middle of the month if a sunny and dry Spring is forecast, otherwise wait until September.

The NOSSA Spring show is only a month away. Start preparing your specimen pots for the display. Any spare pots can be sold on the trading table. There are never enough terrestrials on the trading table at the show to meet the demand.

Photograph your orchids when the flowers are at peak condition. Then hand pollinate a flower or two to get seed for the NOSSA Propagation Workshop or for sowing around mother plants next autumn. Prepare two pots of each species, one for showing and one for seed.

 

How to hand pollinate.

Look closely at the flower column to see the positions of the pollen and the stigmatic surface. Flowers can be self-pollinated if there is only one. Fatter pods with more viable seeds result if two plants of the same species are cross pollinated. That is transfer the pollen from one flower to a flower on another plant. Cross pollination mixes the gene pool to prevent inbreeding. Use a toothpick or a she-oak needle to touch the pollen which will stick to the wood. Wipe the pollen across the stigmatic surface of the other flower and the job is done.

If pollination is successful, the flower will collapse in a few days and the ovary will start to swell. For greenhoods the stigmatic surface is halfway up the front of the column. Remove the front of the flower and the lip so you can see what you are doing. Greenhoods have yellow pollen. For Diuris and Thelymitra the white pollen is hidden behind the sticky stigma. Caladenia have yellow pollen under flaps at the top of the column. Stroke upwards to open the flaps as would an insect backing out of the flower. The stigma is a hollow sticky depression just below the pollen. You will have to tip the flower right back to see it.

Monthly Terrestrial Orchid Culture – July

Continuing Les Nesbitt’s articles from the NOSSA Journal, this month’s (Vol 43 No 6 July 2019) is a relaxing time.

Midwinter is cold and cloudy most days. July is often the wettest month as well. A good time to sit by the heater and read orchid books or search the internet as you plan future activities. Tidy up your records and draw up a wanted list of terrestrials to purchase or swap. Activity in the lab continues with seed sowing and replating. Deflasking should wait until spring as tiny seedlings rot away if planted out in winter. Pots showing any signs of rot should be moved out of the
rain to dry off.

Not a lot to do in the orchid house except observe your orchids and watch for pests that are always looking for a feed. Growth will be slow. Give plants as much sunlight as possible. The very first seedling leaves may appear this month around mother plants. Give yourself a pat on the back if you see any seedlings. More may show in August & September.

Corybas flower this month and do not mind being cold and wet. Corybas flowers will shrivel up if the surrounding air is dry. Mist them daily or place a clear cover over the pot & the flowers will last for weeks. A tall plastic sleeve around the pot or an upturned glass bowl can be used.

Orchid clubs hold their Winter shows this month. Check them out for additions to your collection.

Monthly Terrestrial Orchid Culture – June

It’s June and the the orchids tubers are on the move. And yes there are some tasks for this month but as can be seen by Les Nesbitt’s notes in the June 2019 NOSSA Journal (Volume 43 N0 5) there is not a lot to do.

Diplodium robustum  (syn Pterostylis robusta) – one of the cauline greenhoods


June is cold, often with frosty mornings and sunny days. Terrestrials can take -20C but any colder results in permanent damage. If you live in the country, you may need a solid roof for frost protection. Frosts are rare these days in Adelaide. I have black rubbish bins full of water under the benching in my glasshouse to moderate the temperature. The bins absorb heat in the daytime and radiate it out at night. If it is not frosty it will be cold wet and cloudy. Growth will be slow and there are few flowers out. There is not a lot to do in the terrestrial house.

Pterostylis robusta and Acianthus pusillus flower this month. If there are no flowers this year, they probably aborted due to high temperatures or excessive dryness over summer/autumn. Try putting the pots under the bench in a cooler position next summer.

The last of the terrestrial orchid leaves should appear this month although there are always a few stragglers. Tubers that formed in the bottom of a pot have a long way to grow to reach the surface. Sometimes they come out the drainage holes. If no plants appear, do not throw the pot away. Sometimes orchids take a year off and send up a leaf the following year. They are capable of forming a new tuber from the old without making a leaf. Gather together the “empty” pots in a corner. They can be left for another year or you can knock them out next month to try to establish what can be improved. Most weeds have germinated by now so weeding gets easier.

It is hard to drag yourself away from the heater this month but at least once a week go out on a wet night with a torch and examine your orchids for slugs, snails, earwigs, cockroaches, grubs and beetles. They always feed on your best orchid buds.

The SAROC Fair is in June. Clean up your flowering pots for the NOSSA stand. Other orchid clubs hold winter shows in June & July. Go along and see if there are any interesting terrestrials on the trading table.

Monthly Terrestrial Orchid Culture – May

The following article by Les Nesbitt is taken from the Native Orchid Society of South Australia Journal, May 2019, Volume 43 No 4. The article has been slightly modified with editorial changes in black.

The majority of terrestrials will have leaves showing by month’s end. A few stragglers like South Australian Corybas and Western Australian Cyrtostylis huegelii will not appear until June so do not panic yet.

Pterostylis truncata (little dumpy) flowers this month with a large flower on a short stem. This species is given a blue tag to denote watering from January otherwise there will be no flowers under Adelaide conditions.

Tasks for May

  • Move the Autumn flowering greenhoods under cover as the flowers open because they generally have tall thin stems that will bend over under the weight of rain drops on the flowers.
  • Rot can be a serious problem in May. Do not overwater if there is little rain; and inspect plants closely and often. The rot can be on the leaves or below ground. Look for plants that are not thriving and give them a gentle tug to see if there are any
  • Move infected plants away from healthy plants to a hospital area under cover. Water from below by standing the pot in a saucer of water. Keep the leaves dry. Good air movement and at least 5 hours sunlight a day are essential for the next 3 months.
  • The fast multiplying orchids will appreciate a weak dose of liquid fertilizer once a month until spring.
  • Weeding is a chore this month as weed seeds germinate after rain. Pull them out while they are small maybe even with the help of tweezers.

Virus

Inspect plants closely for virus as the symptoms show in the emerging leaves. All plants can be infected with viruses of which there are many. There is no cure for virus. Infected plants must be destroyed to prevent virus spreading to healthy plants via sap sucking insects or human activities spreading sap. Infection during the growing season does not show up in the leaves until the following year. It is difficult to eliminate virus entirely hence the need to be vigilant.

Signs of Infection

  • Virused Pterostylis leaves may have light & dark green blotches or be thicker than normal and look crippled or turned up at the edges.
  • Another sign to look for are pointed pimples on Caladenia and Pterostylis
  • Virus is harder to spot on the narrow leaves of Diuris and Thelymitra. Healthy leaves are straight with almost parallel sides. Leaves that have kinks or are curved probably have a virus. Variegated blotching may be present in severe cases.

Managing

  • If only one or two plants, in a community-pot, show symptoms they can be lifted out soon after the leaves appear and before side stolons form.
    • A tool can be made from wire to do this. Bend a foot on the bottom of the wire and a loop handle on the other end.
    • Push the foot into the mix alongside the infected plant, rotate the foot under the tuber and lift the plant out.
  • At potting time (when tubers are dormant)
    • A sieve is a great time saver during repotting but at the same time an excellent way to spread virus.
    • Do not shake the sieve when tubers are present.
    • Pick out the tubers as you see them and drop them into a smaller kitchen sieve sitting in an ice-cream container of water. The sand and dirt wash off and falls through leaving clean tubers behind.
    • Use a jet of water to remove any remaining dirt.
    • Pat the lumps of mix in the big sieve to crush them to expose any tubers.
    • Shaking the sieve is the equivalent of sandpapering the tubers, a sure way to spread virus.
  • If several plants are virused it is better to dump the whole pot, soil and all.
  • Refuse new plants that look suspect.

ALL EFFORTS SHOULD BE MADE TO ELIMINATE VIRUS FROM AN ORCHID COLLECTION.

Pterostylis 'Nodding Grace'

Monthly Terrestrial Orchid Culture – April

The following article by Les Nesbitt is taken from the Native Orchid Society of South Australia Journal, April 2019, Volume 43 No 3

Terrestrial Culture – April
Les Nesbitt

The days and nights are cooling down, evaporation rates are dropping and pots take longer to dry out so decrease the watering. If in doubt wait another day before watering. Regular rain usually begins around Anzac Day. There is nothing like a good rain to make terrestrial leaves pop up almost overnight. A few early flowers are out this month – Eriochilus species and possibly Pterostylis truncata. Keep up the pest control and pull out weeds while they are still small.

Sow seed on pots around mother plants of fungus dependent orchids this month. Mix seed & fine sand together to avoid wasting precious seed. A pepper shaker helps spread the seed evenly. Water gently to wash the seed into the mulch.

April is a good month to deflask terrestrials. Seedlings need to establish & harden up before winter so get deflasking completed by the end of April. Check out flask suppliers for that special species. The next deflasking opportunity is early spring.

Deflasking Terrestrial orchids

Prepare a suitable soil mix for the orchid to be deflasked along with labels & sheoak topping. Use the same mix as for adult plants.

Select a flask with strongly growing seedlings, preferably with small tubers but plants without tubers are OK. Remove the flask lid and tip the mass of plants and agar into a fine sieve. If you are nervous remove clumps of plants from the flask with tongs. Try to minimize breakages. The junction of leaf & tuber is very weak. Over a sink or lawn, use a jet of water to wash away the agar leaving clean seedlings behind.

Fill a pot with mix to within 2 cm of the rim and tamp down. Select small clumps of seedlings and stand them around the edge of the pot. Insert a label with the appropriate info as this pot will not be repotted for 2 years. Pour a handful of mix into the centre of the pot and gently squeeze mix out around the seedlings just covering the bases but not burying the leaves. Add more mix if necessary. Tamp down the mix in the centre of the pot. Add a layer of chopped sheoak needles. Water gently to settle the mix around the seedlings.

The pot can go into the shadehouse with other terrestrial pots although it helps to keep all the seedling pots together in a sunny place with good air movement. Ensure the pot does not dry out. If kept too wet the seedlings may rot. If the seedlings establish and grow strongly they can remain in the shadehouse over winter. At any sign of rot move the pots out of the rain under cover and water by standing the pot in a saucer of water.

Next dormant season as soon as the leaves have died down, add more mix to completely fill the pot. This helps to protect the tiny seedling tubers from drying up in the heat of summer. After the second growing season the tubers should all be large enough to find easily at repotting time.

Monthly Terrestrial Orchid Culture—March

As stated last month, this is the second in the series of terrestrial culture notes for growing orchids in Adelaide.

Terrestrial Culture—March

Les Nesbitt

The growing season is underway although much of the activity is underground out of sight early in the month. Repotting should be completed by now. Repotting tubers with long shoots is a tricky business requiring very gentle handling. Broken shoots and the death of some plants can result. It is better to leave them until next summer.

The weather can be hot up until equinox on about March 21st.  Be aware that autumn is a time of rapid change. Day-length decreases by 2 hours in the 6 weeks from the 1st of March. Our orchids respond to the longer cooler nights faster than we do. All pots should be in their growing positions for the coming winter. Increase watering in March so that by equinox the mix is damp right through to the bottom of the pot. The first Eriochilus cucullatus flowers are usually open by the last day of March with the majority blooming in April. The buds resemble a grain of wheat when they first emerge.

Eriochilus collinus

Eriochilus collinus (syn Eriochilus sp Adelaide Hills, Eriochilus aff cucullatus)

Thrip can be a major problem this month. Thrips love to suck on the flowers and will cause the flowers to shrivel up in a day or two. If using a pressure pack fly spray to kill thrips, hold the can at least half a metre away or you can freeze the flowers with the propellant. Repeat the spray every few days.

Pull out any weeds that germinate while they are still small. The early Greenhoods will be showing leaves and some of the blue tag Diplodiums may be showing buds. The Greenhoods will like a weak soluble fertiliser sprayed on their new leaves as they develop.

Deflasking can be done after equinox. April is the best month to deflask terrestrials as it is cooler and more humid with enough sun to harden the leaves before the cold and damp of winter. Flasks are often the only way to get the slow multiplying terrestrial orchids. Seedlings in flask that have tiny tubers establish more successfully.

Diuris tricolour in flask

Remove the second layer of shadecloth at the end of the month or first week in April. Keep up the night time hunts for pests which get more active as the nights cool.

Autumn is a good time to build or extend a terrestrial growing area. A terrestrial house should be sealed to keep out birds and animals and have shadecloth or wire mesh sides to allow the breeze to move through. I prefer a roof of angled 50% shadecloth. Other growers use a solid roof of plastic sheeting. A solid roof means you have to water your pots by hand, which is more work. It is very important that winter sun reaches your plants so site the shadehouse away from the winter shadows of buildings, high fences and evergreen trees. Galvanised mesh benching about 750 mm high will deter slugs and snails and is a convenient height for observing the pots.

food healthy nature forest

Photo by PhotoMIX Ltd. on Pexels.com

Monthly Terrestrial Orchid Culture – February

The following article by Les Nesbitt is from Journal of the Native Orchid Society of South Australia, February 2019 Volume 33 No 1. It is the first of a monthly series that Les is planning to produce for this year.

It should be noted that February in Australia is late summer and dry; and that this article has been written for Adelaide growing conditions. Many of the terrestrial orchids have been dormant.

Terrestrial Culture — February

The excitement is building with the new growing season about to commence. First leaves on the early species may show this month so start looking. Look with your eyes not your finger. Many a new shoot has been broken by that dastardly finger. Keep the blue tag pots moist. Blue tag orchids include Diplodiums, Ptst. baptistii and Corybas hispidus, all species from the East Coast of Australia.

Repotting and Watering

Finish repotting as soon as possible. Many tubers start shooting this month and are easily damaged by handling. Move all pots to their growing positions for the coming winter. For local orchids adapted to a dry January-March, commence watering in the last week of February and increase watering in March. The water will run down the side of a dry pot and out the drainage holes leaving a dry plug of mix in the middle where the tubers are. Watering three days in a row should wet the pot right through. Continue light watering weekly, so pots do not dry out completely again. Top up the cut she-oak needle layer on pots as needed. This is very important for the fungus dependent species which do not get repotted often.

Diuris tricolour in pot

Topped with she-oak cuttings

Hunting the Grubs and Slugs


Start the nightly visits to pick off the slugs, snails, earwigs and grubs. Hunts are more successful on cooler nights after rain or watering. If the new shoots get eaten off as soon as they appear you might not even see them and wonder why your orchids did not come up.

Labelling

If the names on labels are starting to fade rewrite them before the name is lost. Remember to pot up any spare tubers for raffles, stalls and the tuber bank later in the year.

Diplodium


The cauline group of greenhoods (Diplodium) from the eastern states are the first to shoot and ideally should have blue tags and have been repotted in January with watering commencing at the end of January. There are some 38 species in this group. Some come from high altitudes in NSW/Vic and start flowering there in February. They flower in March/April/May in Adelaide.

Diplodium in cultivation

Diplodium robustum – one of the cauline greenhoods, with both flowering and non-flowering plants


Points to note about Diplodiums:

  • Flowering plants look different to non-flowering plants. Flowering plants have small pointed leaves on the flower stem. Nonflowering plants have a rosette of rounded leaves flat on the ground. Usually there are only a small percentage of flowering plants.
  • They flower early in the growing season. Most flower in autumn with a few stragglers in winter. None flower in spring.
  • The rosette plants multiply and are easy to grow in regular terrestrial mixes. New tubers form in Autumn.
  • Diplodiums are not easy to flower in Adelaide. Flowers abort if too hot and/or too dry. Grow them in the coolest shady area there is. Keep pots shaded until late March. Local species are easier to flower as they flower in winter.
  • Poor tuber development from flowering plants is common. These plants sometimes die after flowering.
  • Flowering plants can be tall & slender and may need supporting with a wire cylinder. Stakes can damage the developing new tubers.

 

For additional information on growing terrestrial orchids click here 

Orchids in the Snow?

It’s Christmas and usually, despite Australia’s hot climate, we associate Christmas with snow and cold but we don’t tend to associate them with orchids. And yet, for Australia we do have not one but two Christmas flowering orchids in snow country, that is, on the isolated sub-Antarctic Macquarie Island, an island where “[r]ain and snow are frequent, with only a few days each year with no precipitation”. Admittedly at this time of the year, being summer it is warmer with an average temperature of 7.9degrees Celsius.

The first species was only discovered in 1978 and not recognised as an unique species until 1993 when it was named Corybas dienemus (syn. Nematoceras diemenum). Previously it had been linked with Corybas macranthus.

The second orchid species is  Corybas sulcatus (syn. Nematoceras sulcatum) and this species, possibly the world’s rarest orchid, has gone travelling. Staff from the Royal Tasmanian Botanical Gardens have manage to collect and amazingly propagate the seed.  Amazingly because orchids, particularly the terrestrial orchids, are difficult to grow. It is now flowering, this Christmas season, but under very carefully controlled conditions in Hobart.

Click here and here to see images and read about this amazing journey.

So Christmas, orchids and snow do go together in Australia, albeit in the far flung island of the south.

Corybas sulcatus (Grooved helmet-orchid) is one of two endemic orchids which occur on Macquarie Island (Photo: Royal Tasmanian Botanical Gardens) Image Source

Reference

https://en.wikipedia.org/wiki/Nematoceras_dienemum accessed 23 December 2017

http://www.antarctica.gov.au/living-and-working/stations/macquarie-island/location/climate-weather-tides accessed 23 December 2017

http://www.antarctica.gov.au/news/2017/sub-antarctic-orchid-shows-true-colours-far-from-home accessed  23 December 2017

 

2017 October Cultural Notes

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

Epiphytes

  • October sees many native epiphytes finish flowering and shortly it will be the best time for potting on and division as new growths are due shortly. The earlier you start, the more time the orchid has a chance to initiate new growth and mature it in time for next years flowering.
  • Remove spent flowers as leaving them on the plant in wet and humid conditions leads to rot caused by botryitis.
  • Be aware that aphids are in big numbers now and will cause grief to flowers and new growths.
    • Malathion at 1 ml/ litre of water will knock them out.
    • Repeat fortnightly for 6 weeks to break the breeding cycle.
  • Apply lime to plants grown in bark to counteract acidity.

Terrestrials

  • Most terrestrials nearing completion of the season.
  • Start drying off once leaves start yellowing. Keep water up to those staying green.
  • Additional shade helps now as suns intensity increases

Epiphytes in flower (1)

Annual NOSSA Spring Show