Opinion: Tough tamarisks can be divisive
The tamarisk trees at Devlin Pool Road, Greenough, were part of the focus of this column a couple of weeks ago and drew a lot of comment from people on the Greenough.
From the genus tamarix, the hardy tamarisk is listed as a weed of national significance.
We took another road trip down to the Greenough to bring you more tamarisk stories.
You will see the tamarisks both east and west in paddocks around water troughs, around old buildings and lining driveways.
The house that is closest to the highway along this section is called Lily Cottage.
It is on the west side and easy to spot with its new picket fence.
It is also called Armstrong Cottage, after one of the residents who was once the mayor of Geraldton.
It is a residence that has existed on the front flats for more than 140 years.
Lily Cottage, named after flowers that grew near it, was owned at one stage by Tim and Meta Anderson (nee Harrison).
Ian Harrison lived over the hill and caught the bus to school from his auntie’s residence at Lily Cottage.
He rode the sulky in 1947 with other children, and in 1950-54 he rode a horse on his own. He remembers the tamarisks were always there, so estimates a possible planting time of before 1945.
In more recent times, considerable effort has gone into management of tamarisk trees on this property.
In 2013, Meryl and Paul Hilyard bought the property and they moved there two years later.
In 2018, they removed three large tamarisks.
Most were about 20m-30m high.
A professional tree cutter trimmed the branches of the rest.
There was one large branch leaning over the driveway towards the highway.
Paul Hilyard and a friend Peter Hannaford from Rock of Ages finished the stump to its current shape.
This year, a line of tamarisks on the north of the block was trimmed in preparation for a boundary fence.
A small front-end loader was used to remove the 30cm thick layer of debris from the tamarisks, possibly the first time this has been done since they were planted.
Three snakes were observed among the debris so they may like the thick mass of needle-like leaves as a habitat.
The leaves made a pile 1.5m high and burnt for five days.
You can cut down a tamarisk three times and it will continue to grow back.
Some use a method of burning off the stump. It is a testament to the persistence of the tamarisk tree that it takes so much effort to permanently remove them.
Meryl and Paul removed one close to a shed with a stump grinder as a permanent solution.
Other stumps have been seen sprouting out large branches.
Nothing much grows under the tamarisk tree. There is one green ground cover — possibly a form of saltbush — that grows directly underneath the branches.
One plant Meryl has planted underneath is a lavender that is still surviving.
Another is the bougainvillea near the base of tamarisks.
Meryl and Paul had observed branches growing through the brick wall of a shed on their property before they purchased it.
It had caved in the roof of the shed.
One tree had grown around a wagon wheel and blades from an old windmill.
Looking further south along the highway, you can see some tamarisk trees behind the Greenough Museum and Gardens.
Branches from these are overhanging the highway.
Given the local knowledge of branches dropping, is this a risk factor for travellers?
Locals can tell you what the points for and against tamarisk trees are.
- They grow rapidly.
- Very resilient and require minimal water to survive.
- Long life span.
- Effective wind break.
- Are they termite proof? No observations of termite trails on tamarisks trees or cuttings. Perhaps this is an advantage as dead branches take longer to decompose.
- Goats have been observed climbing and nibbling on the leaves.
- Flowers are an attractive spiral shape that can only be noticed with close observation.
- The dew from the leaves is saltier than sea water.
- Do not park a vehicle under a Tamarisk tree. Salt will affect the paintwork.
- Sheds downwind will rust rapidly promoted by the salt from the leaves.
- Do not put leaves into your compost. You will increase the salinity.
- The roots are aggressively invasive.
- They are very hard to permanently remove. It can take years. They will rapidly grow back after trimming and fire. They will require repeated doses of chemical treatment.
- They are a last option as a nesting place for birds. Very few species of birds have been observed nesting in them.
- They increase the salinity of soil at surface level.
- Their pollen is a health hazard to people with chest issues.
NOTE: Tamarix trees (Athel pine) are a declared pest under the Biosecurity Agriculture Management Act (2007), section 22 (2). While the species is exempt from a Keeping Permit, as a declared pest, it should not be planted in Western Australia. It has potential, given the right conditions, to spread and cause significant impact on banks and flats along rivers and creek.
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