Our Poplar Gum, Eucalyptus platyphylla, is a huge tree. It gives us shade, it is home to innumerable birds and insects and attracts even more when it flowers, and it survives cyclones without falling on our house. But it has an irritating habit of dropping all its leaves and giving us (mostly me, I have to grumble) a lot of extra work.
I have been trying to keep track of just how many times per year its loses its leaves, and this post is part of that effort. For the record, then:
- It started losing leaves a couple of weeks ago and has now lost almost all of them.
- It lost a lot, but not all, of its leaves when it flowered in August.
- It lost some at the end of the Wet, in mid-April.
- It was losing them at this time in 2011, too.
- It lost leaves in September 2011 ‘for the first time since Yasi’ (Feb 2011).
This page about poplar gums on Magnetic Island mostly confirms my observations:
The poplar gum flowers from August to October and, unusually for eucalypts, drops some of its leaves when flowering. In good years it may only lose a couple of leaves but in extraordinarily dry years it can drop its whole canopy.
Another article* about the same species south of us, near Rockhampton, complements it:
The old bark is shed each year to reveal a new trunk of the most exquisite salmon-pink, eventually hardening off to the familiar smooth white trunk. In the late dry season water stressed trees will lose almost all their leaves, while those with access to water will drop their old leaves about the same time as the new ones appear. Flowering is from November to December, the flowers are white and in clusters.
That’s almost enough to see a pattern, isn’t it: it drops its leaves in response to water stress, and the extra energy it needs for flowering adds to any water stress it may be experiencing.
The leaf loss we saw in April doesn’t rate a mention in any references I could find. That may be because it is typically partial – I don’t know.
I do know that I have to go and rake my lawn – again!!
* Link deleted August 2019 because the site has vanished.