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Mark Paisley Lawn Mowing & Landscape Maintenance

Member of Independent Lawn Mowing Contractors Of Australia

 

Mark's Articles Topressing LawnsFertiliser & Chemical Application,  Winter Grass Control, One Black Day Mark's Articles

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WINTER GRASS (POA ANNUA) CONTROL

Poa Annua: Click Image to Enlarge. Image provided by Indmowing

The observant lawn contractor will no doubt notice these soft green tufts or clumped weeks in many lawns at this time of year. 

Some clients will be asking their contractors to spray the winter grass.  Other contractors should be recommending to their clients that the winter grass be sprayed.  They may ask why?  Well the reason for controlling winter grass is simple, it is a prolific seeder and will eventually overtake the lawn in winter and then seed and die off in spring leaving a weakened lawn that will only be infected with more w inter grass next winter.

As a week of turf, winter grass can be found in all situations from home lawns and turf farms to the more intensively managed fine turf of golf and bowling greens.  Winter grass is widespread throughout Australia and is a significant weed problem in many situations.  Winter grass will set seed even in very low cutting heights.

Control & Management

The key to controlling winter grass lies in it's management using both chemical and cultural practices.  Good cultural practices means keeping the lawn well maintained by regular mowing and fertilizing and not allowing bare patches to develop which will offer an ideal seed bed for winter grass germination.

Light infestations may be easily hand weeded as winter grass has a very shallow root system. 

Chemical Management

There are two main ways of approaching the management of winter grass with chemicals... pre emergent or selective post emergent.

Pre emergent control means spraying the lawn before the weeds have germinated.  This is probably not the best way to go for the contractor as application of these chemicals is critical to achieve results and the chemicals are expensive.  Post emergent spraying is the way to go, but you must spray before seed heads form.  These chemicals are also more affordable for both clients and contractors.

Chemicals & Application

Pre Emergent

There are probably more pre emergent chemicals around than I will mention here but these are the ones I have had success with.

KERB - active constituent PROPYZAMIDE, registered for use in QLD, NSW, VIC, SA, WA

Rates:

    Common Cough: 12 grams/100m2

    Buffalo Grass:    12 grams/100m2

    QLD Blue Cough  6 grams/100m2

Apply during Autumn and Winter.  Best results are obtained when application is made to cool, wet soil.  Use only on established turf.  Sufficient water should be used to ensure uniform coverage. 

Irrigate immediately following application with equivalent of 12mm rainfall, and repeat after 24 hours.

Do not re-sow for 60 days after treatment.  Do not use on bent grass, blue grass, rye grass or fescue.

Kerb is an excellent pre emergent control.  It comes in 1.36kg boxes it is a dry powder so must be weighed out correctly and the before and after watering must be carried out.  This makes it a difficult job.

EXPORSAN - active constituent Bensulide registered for use in all states.  Rates are 300mls - in 150-200 litres of water per 100m2.  For use on bent grass and QLD blue couch.  Apply to bent grass in Jan/Feb water in immediately after application.  Do not re-seed with desirable grasses with 4 months of treatment.

Post Emergent

Probably the most common and readily available.  Post emergent herbicide is Endothal or Poa check active constituent - Endothal rates are 15ml in 5 to 10 litres of water per 100m2.  Registered for use in all states.  Apply when winter grass is becoming evident.  Otherwise, apply 2-3 sprays spaced 10-14 days apart in late winter to early spring.  It is important to spray before seed heads form as new germinations will have to be re-treated.

Endothal comes in 2 liters but smaller amounts are usually available from hardware stores or nurseries.  This is the easiest and cheapest form of control for contractors to use.

It is important that when spraying any of these chemicals, that you following the rates on the labels and apply them evenly over the lawn.  Investing in some good quality spray equipment is money well spent.

There are some combination controls for winter grass.  These are fertiliser and chemical combinations.  The one for winter grass is SCOTTS PRE M.  These however need to be applied regularly for good results.  PRE M will also control summer grass.  Rates are around 2.2kg per 100m2.  It comes in 22.7kg bags and is probably not the most cost effective control for lawn mowing contractors to use.

At the start of this article I have used the botanical name for winter grass being Poa Annua it is not a bad idea for contractors to become familiar with some botanical names as common names may differ from area to area and state to state.


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