Category Archives: Fire

100th post: Questions and Answers

Wow, 100 posts, and I was never keen on writing those English essays!  So as promised this post will be a Questions and Answer post, and thank you to everyone who submitted a questions.  They are good questions and I will try my best to answer them.

Do Australian Orchids have one season?

In Australia one or more orchid species will be flowering at any given time of the year.  Currently our summer orchids are in flower, although many of the summer orchids actually grow in swamps and thus are rare.

The moose orchid only grows in swamps in South Australia and flowers

The moose orchid only grows in swamps in South Australia and flowers between November to April

As I was curious as to the number of species flower per month, I took all the species that grow in South Australia and plotted them for each region.  In the northern parts of South Australia due to desert there are only one or two species present, which tend to flower in spring.  However in the southern, wetter regions, there is more likelihood of finding an orchid in flower any time of the year.  From the averages of all the regions it can be seen that the peak in the orchid season is at September to October (the beginning of Spring).

The number of species flowering per region

The number of species flowering per region – Click on image to enlarge

As a keen photographer, I would love to know – in a general sense – where you find a lot of your orchids?

Generally I don’t say where I find orchids partly because some of the sites that I visit are sensitive and it is not wise to have a large number of people visiting the locations.  Also with some of the rarer species, in particular the Duck Orchid, are prone to digging because people do not realize how difficult they are to grow.  No one, not even the experts have been able to grow it.  It is also illegal to take any plant (even picked flowers or capsules) from the wild without a licence.

The duck orchids can not be grown

The duck orchids can not be grown

However there are a lot of locations were you can find orchids.  Where there is native habitat in good condition, there should be orchids.  These include the Mt. Lofty Botanic Gardens (I was up there last Saturday and Dipodium are still flower – even some in bud!), Morialta Conservation Park (take the track on the left to the second falls as it has numerous winter/spring orchids growing along the edge), anywhere in Belair National Park which is a hive for orchids and actually has a few rarer species growing there.  There are many other locations in the Adelaide Hills where they can be found.  Pretty much it comes down to having quick eyes and knowing what habitat the different orchids like.  Anywhere where there are few weeds, there will generally be orchids growing.

A really good way to discover more locations and orchid species is to join an orchid club and go on an excursion with others.  I personally would recommend the Native Orchid Society of South Australia, but have I mentioned that I am their Assistant Editor?!

Arachnorchis tentaculata

The King Spider orchid – Arachnorchis tentaculata – found at Scott Creek Conservation Park

There has been a fire in the Belair National Park, is it likely that there will be a flush of orchids in the fire location come Winter/Spring?

Fire and orchids is such a complex topic.  For those who aren’t local there was a bush fire which occurred a couple of weeks ago in a national park pretty close to the city of Adelaide.  This coming season I would expect to see more orchids flower in that area, in particular the fire orchid.  I will be checking it out later this year to see what happens.  I’ve written about orchids and fire previously.

However there are long term effects of fire that are still being researched.  The following article is highly recommended reading:

Black Saturday Victoria 2009 – Natural values fire recovery program by Mike Duncan

Why some orchids have the trigger mechanism and some don’t?

What a lovely questions – I wish I knew the answer!  There are a number of species that have labellums that can move, from Pterostylis which flowers in the winter to the Duck Orchids which flower in late spring.  They all have different pollinators and the flowers look different.  The trigger mechanism is just one method for being pollinated.  Other orchids use different methods such as imitating a female insect or imitating another flower.  This article could be of interest:

Notes on the Anthecology of Pterostylis curta (Orchidaceae) by Peter Bernhardt

The labellum of the Bunochilus viriosous (also known as Pterostylis viriosous) can be triggered. Photographed in Hardy Scrub

The labellum of the Bunochilus viriosous (also known as Pterostylis viriosous) can be triggered.
Photographed in Hardy Scrub

What is the meaning of life?

The meaning of life is…             [unable to compute]

Thank you everyone for your questions.  I learnt a few things from writing this post and I hope you did to.  Orchids are so complex and amazing!

Orchids and Fire

Many fires in Australia have caused harm and resulted in huge costs. There have be several major cases of fires causes sever damage and fatalities, including Ash Wednesday in 1980s in South Australia and Black Saturday in Victoria, 2009.

Image Source

However there are several orchids that thrive following a summer fire.  These include the black fire orchid (Pyrorchis nigricans), the rabbit ears orchid (Leptoceras menziesii), and the leek orchid (Prasophyllum elatum).  Let me make it clear, they need a summer burn.  In Australia we have a fire season during summer, when no controlled burns are allowed.  Sadly this is when the orchids need the fire, so it is generally the accidental fires or arson which provide the right conditions.  During the autumn and winter months, controlled burns are conducted to prevent the bushland becoming a fire hazard in summer.  Yet these burns often occur just as the orchids are emerging, and can kill the plants.

Pyrorchis nigricans

The black fire orchid, Pyrorchis nigricans, as its name suggests, appears to benefit from a summer burn.  Its leaves are very common, and can grow up to a 5cm across (which is enormous for an Australian terrestrial orchid!).  They usually need fire to flower.

Pyrorchis nigricans

A typical flower after fire

After flowering, the whole plant turns black, hence its name, the black fire orchid.  This picture was taken in summer.

The Rabbit Ears Orchid, Leptoceras menziesii, seems to flower better after a fire.  Below is a lovely patch that my father found following an a fire.  Unfortunately I did not get to see the patch, and have only seen a couple of flowers at a time.

Leptoceras menziesii

One of my favourite orchids after flower would have to be the leek orchid, Prasophyllum elatum.  For this genus, generally the flowers and stems are green, but after fire, the flowers and stems turn black.  They look like black twigs sticking up out of the ground, so blend in quite well with their surroundings.

Without fire

Without fire

A lovely tall specimen

A lovely tall specimen in a burnt area

Striking colours after fire

Striking colours after fire

… and Dad, thanks for the pictures! 😉

The Fire Danger season is over

Or is it?

Fire Danger

April 30 marks the official end of the Fire Danger season.  That means that after May 1, farmers and landowners can do burn-offs, before the rains come.  Principally, control burns are for fuel reduction.

Controlled burns don’t always stay within prescribed limits.  Sometimes, they get out of hand.  Even this week, I have heard of a couple of fires getting out of control.  Of course, they are nothing like the bushfires we have in summer, but they are still a threat.  The fire danger season is not over.

Some Australian native plants need fire to reproduce but the fire needs to be at the right time of the year which happens to be our fire danger season.

Fires in autumn, winter and spring can be dangerous for our native plants, including the orchids.  The Fire Orchid (Pyrorchis nigricans) is one orchid that needs fire in order to flower.  It is quite common with its leaves appearing every year but with only the occasional flower.  It will not flower unless there has been a fire the previous year.  However, the fire has to be in summer while the plants are dormant.  In winter, a controlled burn can destroy the leaves and the whole plant.

Pyrorchis nigricans

Another flower that improves with summer fires are the Prasophyllums.  By improve, I mean they have a striking black stem instead of the standard green stem.

Prasophyllum elatum

Prasophyllum elatum

Leptoceras menziesii produces more flowers after a summer fire.  This seems to be a general trend among the orchids and other Australian flowers.

Leptoceras menziesii

However that being said, there is a lot we don’t understand and don’t know about fire regimes and the Australian bush.