May 2016 Winning Picture

1605 sm PM Caladenia flava

There were four entries this month with two from Western Australia Pauline Meyers’s Caladenia flava and Ros Miller’s Caladenia longicauda sbsp. eminens; one local Greg Sara’s Pheladenia deformis; and one from the Australian Capital Territory, Lorraine Badger’s Cyanicula caerulea.  The winner was the Caladenia flava.

If I was to think of an orchid that represents Western Australia it would be hard to choose between the Queen of Sheba and this one.

With its long flowering season (July to December) it is Western Australia’s most common and widespread species; being found in the south west triangle of the state from Kalbarii to Israelite Bay; in habitat as variable as the coastal heathlands through to inland rocky outcrops; from forests to swamp margins.  Being so prevalent, it is not surprising that it was amongst one of the first Western Australian orchids collected in September to October, 1791 by the ship-surgeon and naturalist, Archibald Menzies. It was subsequently named in 1810 by Scottish botanist Robert Brown.

C. flava is one of the five species belonging to the subgenus Elevatae. The other four being C. marginata, C. nana, C. reptans (all WA endemics) and C. latifolia which is widespread across southern Australia. All five species have the same characteristic feature of the calli joined together on a raised plate near the base of the labellum. C. flava is distinctively and predominately yellow whereas the others are pink or white.

C. flava has two pollinators, native bees which are lured deceitfully to the non-existent nectar and scarab beetles (Neophyllotocus sp.). As they share the same pollinators, C. flava often hybridizes with C. reptans and C. latifolia, producing very colourful offspring.

Observations have led orchidologists to divide C. flava into 3 subspecies. These differences are based upon floral morphology. but curiously they each have their own separate distribution.

References:

Brown A, et al, 2013 Field Guide to the Orchids of Western Australia

Hopper, SD & Brown, AP 2001b Contributions to Western Australian Orchidology: 2, New taxa and circumscriptions in Caladenia (Spider, Fairy and Dragon Orchids of Western Australia), Nuytsia 14:27–314.

CULTURE OF FAST MULTIPLYING (FM) TERRESTRIAL ORCHIDS

Recently, NOSSA updated the Terrestrial Culture Fact Sheet.  Instead of one sheet, it was decided to split it into three – Culture of Fast Multiplying Terrestrials, Culture of Slow Multiplying Terrestrials and Culture of Fungi Dependent Terrestrials.  Though much of the growing information is similar, there are some significant differences of which growers need to be aware.  The first of the fact sheets is Culture of Fast Multiplying Terrestrials.

FLAGBEARER SPECIES: Pterostylis curta

Pterostylis curta Labellum and column 92RL
Pterostylis curta (Blunt Greenhood) is rated rare in South Australia.  Ex situ conservation is another dimension to conservation.

Others include Chilogolottis, Corybas, Cyrtostylis, Diplodium, Microtis most Pterostylis and some Diuris. Most FMs are Autumn or Winter flowering. The exceptions are Diuris and Microtis. FM are the most common terrestrial orchids to be seen at meetings and shows. Once seedlings are established they are no longer fungi dependent.

GROWTH HABIT: FMs are the easiest terrestrial’s orchids to grow. They multiply by forming 2 – 5 tubers per plant each year. The annual growth cycle comprises 6 – 8 months as growing plants under cool (5 – 20⁰ C max, 0 – 14⁰ C min) moist conditions and 4 – 6 months as dormant tubers in hot (18 – 42⁰ C max, 12 – 30⁰ C min) dry conditions.  New tubers are produced in winter/spring. FMs are colony types, ie they multiply annually and will spread out over time if planted in the ground. 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. FMs mainly flower in Autumn and Winter. Diplodium & Pterostylis leaves are usually the first to appear in March followed by Diuris and Microtis in April, and Corybas in June to July. In October/November the leaves go yellow, then brown and dry as the days get longer, hotter and drier in late spring.

LIGHT/SHADE: 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 & Microtis) prefer a brighter location for good growth. Corybas like the shadiest corner.  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 amount of light should be increased.

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 matt 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.

REPOTTING: They grow better if repotted annually otherwise the plants crowd together around the rim of the pot.  Repotting is normally done between November and January. The pots can be knocked out and the tubers examined without harm.  For best results repot the tubers in half fresh soil mix. A suitable soil mix is 40% loam, 50% sand and 10% organic matter with a little blood and bone fertilizer added. (They will also grow in native potting mix.) 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 chopped sheoak needles (20 – 50 mm lengths). This prevents soil erosion and assists with aeration under the leaves.

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 mite and fungal diseases in the warm weather.

FERTILIZING: FMs are very hardy and will benefit from weak applications of folia feed in the early growth stages.

OTHER CULTURE NOTES:

NB: IT IS ILLEGAL TO TAKE PLANTS (WHOLE PLANT, FLOWERS, SEEDS AND TUBERS) FROM THE WILD

 

CLUES TO ORCHID IDENTIFICATION – Prasophyllum & Microtis Leaves

Orchids are attractive and abound in variety. It is the variety that often provides the challenge of identification. As a novice it can be a bit overwhelming. In the eye of the beginner, the experienced orchid hunters appear to have no difficulty with identification. Over the years they have accumulated various clues that guide them toward accurate identification.

This series aims to document the clues that orchid hunters use.

Prasophyllum and Microtis Leaves

The first in the series relates to distinguishing between Microtis and Prasophyllum leaves. When in flower it is easy to see which is which but not so when only in leaf; and as they do not always produce flowers it is helpful to be able to separate them out at leaf stage.

Both leaves are green. Both are cylindrical. Both are hollow. Both resemble onion leaves.

M & P Leaves
Both types of leaves are long, thin and green.  The damaged Microtis leaf (below) shows the hollow.

The differences can be found in one or two areas. Microtis leaves are always green at the base whereas Prasophyllum leaves usually but not always will have a red or purplish coloured base. To help in identification, it is necessary to examine the base by moving the leaf litter aside to see where the plant emerges from the soil.

M & P Leaf Bases
The bases reveal the difference between the two genera.

Prasophyllum species that could have a green base are P. laxum, P. occulatans, P. sp Jip Jip, P. elatum, P. sp Sandplain, P. pallidum (although this is short and usually in bud when noticed), P. spicatum, P validum.  So further observations are necessary.

Another other area of difference is that the broken leaf of a Microtis yields a mucilaginous (thick sticky) sap; the Prasophyllum leaf does not.

Within the segregate genera used by many NOSSA members, there are two other genera with similar leaves. They are Microtidium and Hydrorchis. Again they are green, cylindrical, hollow but only hollow in the lower half. The top half is solid.

It should also be noted that Microtis can form dense colonies but Prasophyllum will never form more than loose colonies.

Finally, if upon gently feeling the base of these leaves it feels solid, that will indicate that there is a bud and it will most likely flower this season.

M & P Flowers
Once in flower, the differences between the two genera is obvious.

A Timely Reminder

This article is reprinted from  Volume 39 No 11 December 2015 Native Orchid Society of South Australia Inc. Journal

Tuber Repotting Time is here

Les Nesbitt

Now that Australian terrestrial orchids have gone into dormancy it is time to think about repotting and preparing for the next growing season.

The best months for this activity are December and January.

I will limit this discussion to the easily grown colony forming terrestrial orchids as these are more likely to be available – for easily grown terrestrials, click here.

IMPORTANCE AND NECESSITY OF GROWING SOUTH AUSTRALIAN ORCHIDS

We need more terrestrial growers in NOSSA to feed the tuber bank and to supply spare pots for sale to the public at the Spring Show. I found it embarrassing to see so few terrestrials for sale at the 2015 Spring Show compared to the numbers available in years gone by.

Growing terrestrials is a rewarding hobby that does not take up much time or space and will pay for itself. Plus you are doing something effective orchids and the environment even if only the most common terrestrials are grown (eg the greenhoods and onion orchids). Consider easily grown, fast multiplying, Pterostylis curta (listed as rare in the SA Act) has been widely grown in NOSSA collections since the days Roy Hargreave’s wash trough when NOSSA was formed.

Once the basic principles are understood it to move onto the rarer species as artificially propagated plants become available in future as they surely will. Members can draw on the tuber bank in December to get started seriously about it as a group of volunteers will be needed within a year or two to help look after the output of a number of projects already underway or about to start.

Year 8 girls at Kildare College have been repotting the school’s terrestrial collection and this is how they did it.

EQUIPMENT

Prepare all the materials needed including:

  • Pots
  • crocking material,
  • sand
  • organic matter
    • blood & bone, native compost, chopped up sheoak needles
  • 4B pencil and labels.

PREPARATION

  • Water the pots lightly a day or two before repotting. The mix should be damp enough to not be dusty, yet dry enough to not stick to everything.
  • Remove the label, wash it in a container of water and stand it aside to dry.
  • Check on the label back to see how many tubers were planted last year.

REPOTTING

Scrape off and dump the top layer of soil as this can be contaminated with moss, slimy bacteria and liverworts.

  • Tap out the plug of soil into a sieve sitting on a bowl. Pick out any tubers that are visible on the outside of the plug.
  • Gently break the soil apart and search for tubers while squashing the lumps of mix through the sieve.
    • Very small tubers may go through especially with Corybas. If you have not got a sieve do this operation on a sheet of newspaper.

Place the tubers in a dish so they do not roll away.

  • Count the new tubers to see whether they increased by 2, 3 or 4 times.
  • Discard anything left in the sieve (old tubers, roots etc.).
  • Work out how many new pots are needed to plant all the new tubers.

Add to the old mix in the bowl

  • a pinch of blood & bone,
  • a handful of sand and a handful of native potting mix.
    • Also add enough of these ingredients for each additional pot and mix the contents of the bowl together.

Select new or sterilised 125 mm standard pots

  • and place a square of shadecloth in the bottom to keep the sand in and critters out.
  • Pour in mix to within 30 mm of the top and ram down with your fist.
  • Place up to 10 tubers on top of the mix.
    • Lay tubers horizontally if unsure which is the top.

Labelling and finishing the task

  • Write out the orchid name on extra labels and fill in the numbers of tubers on the back for each pot.
  • Almost fill the pot with mix and tamp down.
  • Insert the label. Place a layer of cut sheoak needles on top of the mix.
  • Water the pots and the job is done.

For show pots use 175 mm or larger pots and plant 20 to 50 of the largest tubers available.

If the tubers have decreased or look unhealthy, throw out all the old mix and replant in new mix.

20150922_210750
Repotting a Diuris

Related Articles:

Growing Terrestrial Orchids Part One of Four

Growing Terrestrial Orchids Part Two of Four

Growing Terrestrial Orchids Part Three of Four