Parramatta Grass (Sporobolus africanus).

Parramatta Grass aka Rat’s Tail, or Tussock Grass is a tough perennial tussock grass that grows to a height of 50 to 70 cm, and reproduces from seed.

Rat’s Tail is spread rapidly by vehicle traffic, wind and flood water. It grows rapidly, is frost and drought resistant, and produces around 80,000 seeds per plant.

It is a problem weed grass because

• Is a weed in wet areas such like watered turf, roadsides and waste areas.
• It emerges all year round when soil moisture and temperatures are suitable. Spring and Summer is when most seedlings appear.
• Parramatta Grass produces large numbers of seeds, These readily disperse, and the soil seed bank builds up quickly.
• The seeds are viable for a long time.
• Tussock Grass grows in lower rainfall areas, but is most common in areas with an average annual rainfall above 700 mm per year.

 

After you read this, you will be able to:

• Identify Parramatta Grass or Rat’s Tail.
• Know what conditions favour Parramatta Grass.
• Know the best cultural and chemical options to control Parramatta Grass or Tussock Grass.

 

More information on common lawn weeds is in our weed ID chart. What they reveal about soil conditions is in our blog on indicator weeds. Rat’s Tail is an Indication of soil compaction.

The distribution map for Rat’s Tail is courtesy on The atlas of Living Australia.

 

 

 

 

 

Category: Grass

Photosynthetic Pathway: Parramatta Grass is a C4 grass weed.

Flower: The flowers are green or grey.

Height: Parramatta Grass grows to a height of up to 50cm.

Leaf length: The leaves are up to 20 cm long.

Leaf width: The leaves are up to 6 mm wide

Reproduction: The seeds of Parramatta Grass are spread via machinery and vehicles. The seeds become sticky when wet, and then stick to animals and clothing.

Rat’s Tail produces up to 60,000 seeds per square metre, and estimates of the soil seed bank have put it at up to 600 to 4,000 seeds/m2.

Parramatta Grass does not disperse by wind, and even though the seed is small, most seed falls within 2 to 3 m of the plant.

Comments: Rat’s Tail has very tough, smooth and glabrous, dark green leaves. These leaves are mainly around the base, and are slender and stiff, with in-rolled margins. Where the blade meets the stem, the leaf sheath rolls around the stem.

Habitat: Parramatta Grass mostly grows in areas with a moderate to high rainfall. It favours compact soils, and invades low maintenance turf areas.

 

 

 

 

Cultural control is the best option to control Rat’s Tail in lawns and turf grass.

 

Preventing the spread of the seed of Parramatta Grass is the most effective way to control this weed.

Daily fluctuations in temperature, and exposure to light stimulate the germination of this weed. This means if you keep a full turf cover, it reduces these fluctuations, and prevents germination. Any bare or thin turf areas allow the seed to germinate.

You can hand remove small Parramatta Grass plants if there are not too many. However, you must bag the seed head first to prevent seed dispersal. Slashing or Whipper snipping before you use a herbicide also pays dividends.

The key is to try to manage this before it seeds.

• Dig out the plant, and try to minimize soil disturbance.
• Immediately place the entire plant in a sealed bag. Remove this off site asap.
• Regularly re-check the site for new plants.

 

As it favours compact soils, soil aeration also helps to manage Parramatta Grass. Also, bear in mind that keeping N up to your turf grass helps deter this grass weed, as it encourages a healthy turf cover.

 

 

 

There are a limited number of turf herbicides that control Parramatta Grass.

 

 

 

 

 

 

 

 

A 2011 trial into the control of Parramatta grass looked at a herbicide programme of MSMA followed by Tribute followed by a further application of Tribute. The trials showed best results occur in the warmer months of the year, although this only suppressed of Parramatta grass. Full control was not achieved. Tribute Herbicide and MSMA are not currently registered for Parramatta Grass control.

 

 

 

For small infestations of Parramatta Grass use glyphosate. If you intend to use glyphosate be aware that it kills everything it touches. If water quality is an issue (high water pH) then we recommend the use of ProForce Manta Ray Adjuvant.

 

 

The following are non-selective but also have a long term residual and stop re-growth of Parramatta Grass.

• • Renegade. This stops weeds for up to 12 months, and reduces the need for multiple herbicide applications.
  • Numchuk Quad. Numchuk Quad gives effective post and pre emergent Rat’s Tail control for up to 12 months.
  • Cortex Duo. Gives a rapid knockdown of Parramatta Grass, and gives residual control for up to 3 months. Cortex Duo is safe to use around trees.