Category Archives: menziesii

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! 😉

Advertisements

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.