Wild Windellama

by Paul Alessi

September 2005


Serrated Tussock (Nassella trichotoma)

With Spring upon us it would have been good to write about
the fantastic flowering of our native plants now underway but I thought
it more important this month that we consider the greatest threat to our native bush 
and hard earned grazing lands and that is Serrated Tussock. 
Now is the time to inspect your land as once the other pasture grasses
have grown it will be much more difficult to see.

If you don't have any Serrated Tussock then you would certainly be in the
minority of landholders in Windellama and it is sometimes not apparent that you have
this weed until you have a major outbreak, the young plants are the hardest
to see and identify. Immature plants can still set seed and every season
they live they will set more and more seed until they reach maturity with many thousands
of seeds per plant.

To the untrained eye it can resemble a few of our good native grasses mainly Poa Tussocks,
but the seed and leaves of Serrated Tussock and our native tussocks
are very different. The plants most commonly confused with Serrated Tussock is
Snow Tussock (Poa labillardierii) common on creek flats and and the woodland tussock
(Poa sieberiana) mostly found in relatively undisturbed Eucalypt forests.
The leaves of Serrated Tussock are cylindrical and those of most natives including Poa
are folded into a U or V section so a close visual inspection or simply rolling them between
your fingers us useful for identification, if the sample flip flops between your fingers it is 
not Serrated Tussock, if it rolls smoothly then it is most likely Serrated Tussock. The fruiting stems
of both native and Serrated Tussocks are cylindrical so make sure you are testing a leaf blade.

The seeds are very different too as the illustrations show but they are small and
require close inspection, a magnifying glass may be necessary.
Rub the seed heads until the seeds seperate from the husks.

Spraying the wrong species destroys your good native grasses, costs you
time and money and can create bare patches favoured by weeds including
surprise surprise ....Serrated Tussock.

Those that you know to be Serrated Tussock should be sprayed by the end of October 
before seeding commences, if you are still unsure check the suspect plants in November to
early December and look for the first seed heads.

A native of South America, Serrated Tussock appeared mysteriously in the Yass
area a few decades ago. There are a couple of rumours as to how it got
here, one was that was used in the lining of saddles another that it was trialed
for stabilisation of soil erosion areas. It has proven to be the most difficult weed to
eradicate we have yet seen in the Southern Tablelands. It thrives in our climate and soil types,
is mostly immune from extreme heat, cold, or dry and is not fussy which soil types it lives in.
It is also unpalatable to all but the hungriest of grazing animals so will
quickly over run the infested area and the seed can remain viable in the ground
for many years.
The main areas that seem to repel Serrated Tussock invasion seem to be undisturbed 
bushland that have a good canopy cover and even then it can creep in if left unchecked.
Good quality native pasture also seems to hinder infestation and ploughing of these
paddocks can lead to over run by Serrated Tussock.

Once established it quickly takes over completely and each summer at seed
maturation from December onwards the seed is blown from the plant while
still attached to the wispy fruiting stems (panicles) these panicles can be lifted
in the wind and travel both short or great distances which can make you very unpopular
with your neighbours, the weeds inspector or anyone with land downwind.

Properties that have a Serrated Tussock problem can also lose much of their resale
value, most real estate agents will know a Serrated Tussock infestation when they 
see one, Near Taralga there is 250 acre property with about an 80% cover of Serrated Tussock
It has steep stony hills much of which could not be traversed by any vehicle especially one
with a spray unit attached, the owner was desperate to sell but could not find a buyer
because of the weed problem. A mysterious fire was lit burning much of his property
and destroying some of the seed set for that year but the plants recovered quickly.

Goulburn/Mulwaree Council can help with advice and spraying and there are also a number of
local spraying contractors skilled in identification and control of Serrated Tussock.
Chipping them out with a mattock is fine if you only have the odd one and a mattock
should be always be on hand when you go out and about on your property,
Make sure you get all the stems and roots when you chip though as one strand left behind
can survive and grow to be a mature plant. Larger areas will require spot spraying and 
the largest areas will probably need ploughing or boom spraying so early control
will save you money. After ploughing, spraying, burning or slashing any heavily
infested area should be sown or planted out with other grasses that will compete 
with new Serrated Tussock plants that might germinate.

For those few plants that might get missed in your control program seed can also be
carefully hand stripped and placed into bags for burning after the fire season finishes,
transporting Serrated Tussock seed to other places even if it's only for disposal is against the law.
Those plants that seed has been removed from should be sprayed or chipped before
the next Summer season. If you chip any out that have seed on them you will also need
to bag and destroy them.

Successful small scale trials have been done by placing seeding Kangaroo Grass
thatch over former Serrated Tussock areas and then removing the thatch in spring.

There are another two undesirable exotic grasses starting to invade here, African Lovegrass
and Chilean Needlegrass, more on them another time.

Copyright Paul Alessi 2005