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.

Do Any Orchids Grow Near The Sea?

Orchids are found in a wide range of habitats.  One such habitat is the littoral zone or more simply the seaside.  The following information is taken from the NOSSA’s CD/DVD South Australia’s Native Orchids 2011.

The Littoral Zone

Many orchid species have a linear distribution following the coastline. Here on the leeward side of sandhills the air is usually moist and mild, few frosts occur so close to the sea and sea-fogs in winter will cause water to drip into the sand which easily soaks up both the moisture and the extra nutrients provided by sea-spray. Some of the best known coastal orchids include the gnats Cyrtostylis robusta, pink fairies Caladenia latifolia, coast onion-orchids, Microtis arenaria and coastal helmet orchids Corysanthes expansa as well as C. despectans. All of these are colony forming species, mostly because the windblown sand would soon cover ‘single plant’ species which start to appear after the second line of dunes.

Coastal species can be a few kilometres from the sea but there are several that grow either at the high tide mark, within sight or sound of the sea or in coastal dunes. Apart from the ones already mentioned above, the following are some others that can potentially be found within sight and sound of the sea.

  • Acianthus pusillus (Mosquito Orchid)
  • Arachnorchis cardiochila (Thick Lipped Spider Orchid)
  • Arachnorchis fragrantissima (Scented Spider Orchid)
  • Arachnorchis fuliginosa (Coastal Spider Orchid)
  • Arachnorchis sp Brown Bayonets (Port Lincoln Spider Orchid)
  • Bunochilus flavovirens (Coastal Banded Greenhood)
  • Bunochilus littoralis (Lake Saint Clair Banded Greenhood)
  • Caladenia sp Selfing Coastal Dunes (Little Dune Fingers)
  • Corunastylis nigricans (Port Lincoln Midge Orchid)
  • Diuris orientis (Wallflower Orchid or Bulldogs)

    Diuris orientis
    Diuris orientis (Wallflower Orchid)
  • Diplodium erythroconchum (Red shell Orchid)
  • Glossodia major (Waxlip or Purple Cockatoo Orchid)
  • Leptoceras menziesii (Hare Orchid, Rabbit Ears)

    Leptoceras menziesii (Rabbit Ears Orchid)
    Leptoceras menziesii (Rabbit Ears Orchid) after a fire
  • Prasophyllum elatum (Tall Leek Orchid)
  • Prasophyllum litorale (Vivid Leek Orchid)
  • Prasophyllum sp Late Coastal Dunes
  • Pterostylis cucullata (Leafy Greenhood)
  • Pterostylis curta (Blunt Greenhood)Pterostylis curta Labellum and column 92RL
  • Thelymitra antennifera (Rabbit Ears; Lemon Sun Orchid)07 JB T antennifera sm

Unfortunately, where there has been settlement, it is now unusual to find these species so close to the sea.