Ask not when do particular Orchids flower - ask what is in flower where I am now? In winter, it all depends on altitude and temperature.
In the cold Southern Highlands of NSW, there is always a hiatus between the flowering times of Orchids here and the flowering times of the same species of Orchids down on the coastal plain in the Illawarra and Shoalhaven regions (which are less than an hours driving time away). And there is also an intermediate area, along the side of the Illawarra Escarpment, namely half way up Macquarie Pass.
So, it is difficult to be dogmatic about flowering times for a particular species of Orchid (especially in winter). Basically, it depends on where you are looking.
For example, I have seen one (only) "Tall Greenhood" (Bunochilus longifolius) in flower at Gibraltar Falls (south from Nowra) in early April. Alan Stephenson showed the ANOS group many of this species in flower in the Shoalhaven in late May. But, by contrast this species has just started to flower here in the Highlands. They have been in flower for several weeks, half way up Macquarie Pass. They have just started along the Belmore Falls Road, and along Kirkland Road, Kangaloon.
|Bunochilus longifolius - the "Tall Greenhood"|
A related species, Bunochilus tunstallii, is also just starting to flower along the road to Belmore Falls. Sorry about the image quality - it was growing in a flooded creek bed and I didn't want to get wetter than I was already. The dark labellum is the diagnostic feature. I refuse to kneel in water to get a better shot.
|Bad photo of Bunochilus tunstallii.|
Similarly, the Nodding Greenhood (Pterostylis nutans) is just starting to flower along the edge of Kirkland Road, Kangaloon. They have been in flower since mid May at Thirlmere Lakes.
|Pterostylis nutans - the "Nodding Greenhood"|
The Rainforest Greenhood (Pterosylis hildae) has just started to flower in suitable patches (clearings and roadside edges) on Macquarie Pass.
The red backdrop is from a piece of bark - sorry about that.
|Pterostylis hildae - the Rainforest Greenhood, on Macquarie Pass|
For comparison, here is the closely related Pterostylis curta, the "Blunt Greenhood" with its characteristic twisted labellum. They have been in flower on the coast for several weeks, but just starting on Macquarie Pass.
|Pterostylis curta - note the labellum twisted to the side.|
The "Maroonhood" (Pterostylis pedunculata) is now in coming into flower along the coastal plain in the Shoalhaven and Illawarra. These images were taken at Blackbutt Forest Reserve, (in the Shellharbour Council area). with Kirsten, several days ago. I know where they grow up here on the Highlands, and there are no signs of flowers yet (up here).
|Pterostylis pedunculata - front view|
|Pterostylis pedunculata - rear view - note the rounded "bottom"|