The turf weed ID chart

This is an easy-to-use turf weed Identification chart for Australian turf weeds, including lawn weeds. This discusses the conditions that favour common weeds and what your weed control options are. At the end of this article is a section on using identifier weeds.

Firstly three key points in regard to weed identification in turf.

The first thing is, if you use this turf weed ID chart and identify the weed in your lawn or sportsturf you don’t always need to spray a weedkiller. Many weeds usually indicate underlying soil problems so if you deal with these first it discourages the weeds and avoids using turf chemicals. More on this later.

The second thing is that weeds can be either grass weeds (monocots) or broadleaf weeds (dicots). If you can see the weeds when they are seedlings you will get a good start on identifying them. Grass weeds have one seedling leaf and broadleaf weeds have two seedling leaves. Broadleaf herbicides do not control grass weeds.

The third and most important thing is if your lawn or turf is thick and healthy, weeds find it very hard to get a hold!

 

Turf weed control chemicals.

Herbicides and weed control products are classed in several ways:

You use pre-emergent herbicides before weeds emerge and they kill weed seedlings as they germinate and try to establish. They have no effect on weed seeds and are mainly used against grass weeds like winter grass and summer grass although some pre-emergents are effective against broadleaf weeds. Pre emergent herbicides can be either liquid or granular pre emergents.

You apply post-emergent herbicides after weeds appear and they control growing weeds. They can be either contact or systemic like the sulfonylureas.

Contact herbicides cause injury where the chemical contacts the plant. They work best when you apply them to young weeds and examples are diquat, carfentrazone, plant oils, and herbicidal soaps.

Systemic herbicides work better on older weeds and move within the plant and causing injury throughout the target weed. Examples are glyphosate, quinclorac, triclopyr, 2,4-D, dicamba, and mecoprop mixtures (an active ingredient in many broadleaf weed killers).

Selective herbicides kill weeds without damaging turfgrass species as they are toxic to only certain plants or weeds. e.g. 2,4-D kills only broadleaf weeds and not grasses. Non selective herbicides kill all vegetation including turfgrass.

More product information is available in our turf chemicals section or in this free Guide to turf pesticides.

 

Turf weed ID chart

Weeds A-C 

Bindii

photo of Bindii in sportsturf

Thrives in low light and wet soils. Use one of 3-D, Casper, Monument, Contra M, Duke, Warhead. Appears from May to October.

Bindweed

Field Bindweed flowering
Prefers compact soils

Black Medic

Black medic flower

Favours dry, low fertility and compact soils. Use Casper, Monument, Contra M or Duke.

Burr medic 

Burr medic

Germinates in the autumn and winter, and flowers in the spring. Prefers poor, heavy clay soils.

Buttercup oxalis

wood sorrrell is often confused with other weeds. The weed ID chart takes away the guess work. This weed is equally at home in light, medium or heavy soils with acid, neutral or basic pH, but that it prefers dry sites.
Aka Wood sorrel and soursob. Prefers low calcium levels and drought. Use 3-D, Casper, Monument, Contra M, Duke, or Warhead Trio herbicide.

Capeweed

Capeweed

An indicator weed that shows high fertility soils. If the weed is stunted and has a yellow colouration it indicates low nitrogen. It also indicates compact soils and that the turf cover is thin. Often seen in high wear areas where the turf has thinned out.

Carrot weed

Weed chart image of Carrot weed, cotula or button weed.

Also known as common cotula or button weed this favours drought, low fertility and compaction. Control using one of Casper, Monument, Contra M or Duke.

Cats Ear 

Catsear
Aka Flatweed or false Dandelion. Low fertility conditions favour this weed. Use 3-D, Casper, Monument, Contra M, Duke, or Warhead.  

Chickweed

Chickweed

An indicator weed indicating wet, compact soil and low light levels. Control by using 3-D, Casper, Monument, Contra M or Duke herbicide.

summer grass

Summergrass with seedhead
For post emergent control use Gauntlet or Quinstar. Best pre-emergents are Barricade, Battalia or Onset 10GR.

Creeping Mallow

Creeping mallow

If conditions are favourable, most mallows behave as short-lived perennials. Use Contra M

Crowsfoot

Crowsfoot with its distinctive seedhead

Prefers wet, low fertility and compact soils. Post emergent control with Destro and Tribute. For Pre-emergents use Barricade, Battalia or Specticle herbicides.

Weeds D-N

Cudweed

Cudweed
Is a problem all year round. Use 3-D, Contra M, Duke herbicide, or Warhead herbicide.

Dandelion

Dandelion
Prefers compact, low fertility soils. Is a problem from May to August. Use 3-D, Casper or Contra M.

Flaxleaf Fleabane

Flaxleaf fleabane is a tall annual weed

Can occur all year round. Use 3-D, Casper or Contra M. Image courtesy of Weeds of Melbourne.

Flickweed

Flickweed is a common turfgrass weed that favours damp, recently disturbed soils.
Aka hairy bittercress. Found in damp, recently disturbed soil. Occurs in two periods: February, March And April and then August, September and October.

Khakiweed

Khakiweed
Use Casper. Establishes in spring and summer.

Lambs Tongue

Lambs Tongue
Aka Ribwort or narrow plantain. Prefers low soil fertility, droughty and acid soils. Can occur all year round. Use 3-D, Casper, Contra M or Warhead Trio.

Knotweed

Knotweed identification using the weed ID chart

Appears from August to March in droughty, compacted and acid soils. Use Casper or Contra M.

Nutgrass

You can identify nutgrass using the weed ID chart due to its distinctive flower.

Prefers moist, high fertility soils and occurs from September to March. Use Monument or Prosedge 750W.

 

Weeds N-W

 Guildford Grass

Identify Guildford grass (onion grass) using the turf weed ID chart by its purple flower

Aka onion grass. Use Duke herbicide.

This is indicates low soil fertility.

Paspalum

Paspalum
Prefers wet, high fertility soils and is a problem from October to February. For post emergent control use Gauntlet and/or Tribute. Barricade or Onset 10GR are good pre-emergent options.

Slender speedwell

Slender speedwell grows on all soil types, in particular moist soils

This weed grows on all soil types, and likes wet soils

White clover

white clover in turf

This is an all year round weed, and prefers droughty, compact soils with low fertility. Chemical control is easy if you use one of 3-D, Casper, Monument, Contra M, Duke, or Quinstar.

 Winter Grass

Wintergrass identified by seed head and boat shaped leaf tip and distinctive seed head

Favours wet compacted soil, low light and low soil fertility. It generally appears between March to October. Post emergent control: Monument, Duke, Checkpoint, Tribute. Pre-emergent: Barricade, Battalia and Specticle.

Turf Indicator weeds

Weeds are very helpful as they tell us the health of a soil. Once you identify a weed using the turf weed ID chart you can use the table below to discover what conditions favour it. For example, if you have bindweed then carrying out a soil aeration program will create less favourable conditions and possibly mean you do not need to use a herbicide in the future.

Presence Indicates

Weed common name

Fertility

Drought

Wet

Acid

Compaction

Low light

Winter grass

Favours a wide range

Yes

Yes

Shade tolerant

Bindi

Bindweed

Yes

Black medic

Yes

Yes

Capeweed

Common on high fertility sites

Chickweed

Fertile soils with a pH of 6.2-7.0

Yes

Yes

Light shade

Chicory

Fertile soils witha pH of 6.2-7.0

Yes

Creeping oxalis/         wood sorrel

Low Ca and high Mg

Yes

Crowsfoot

Heavy soil

Yes

Dandelion

Low in Ca and K

Yes

Yes

Daisy

Low P, high K and high Mg soils.

Yes

Yes

Fat Hen

Prefers fertile, heavy soils

Flat weed/

catsear

Often low in P and/or K

Knotweed

Yes

Yes

Very much

Onion grass/

Guildford Grass

Low in P

Pigweed

soil pH of 5.6 to 7.8. Indicates too much Fe or too little Mn, P and Ca.

Plantain

Low fertility

Yes

silver cinquefoil

Yes

speedwell

Yes

Summergrass

Very low levels of Ca and P, and high levels of Mg and K.

Yes

White clover

Low fertility especially N

Yes

Yes

Yarrow

Yes

Yes

After using the Weed ID chart how to get the best results.

  1. Correctly identify them. A weed is only a weed if its a plant where you don’t want it. Also if you don’t know what it is how can you control it properly?
  2. A healthy actively growing turf surface is the key to stoppng weeds. If your turf is healthy you are less likely to get weed issues;
  3. Always read the label and MSDS sheet on any turf chemical you are going to use.
  4. Make sure that the herbicide you want to use is safe to use on your turf;
  5. Spot treating is always a good first step. If you use a spray marker dye it allows you too see where you have treated and avoids double treating areas;
  6. In some situations when the weed population is too high you are looking at a blanket application;
  7. A post-emergent herbicide works best when weeds are actively growing. Applying to turf under stress will tend to give poor results;
  8. Some post-emergent broadleaf herbicides, like dicamba, cause tree injury if applied too close to the tree drip line;
  9. The key to success for all pre-emergent herbicides is to apply 2 to 3 weeks before weed germination;
  10. Pre-emergents work best when the soil is moist but the turf is dry at the time of application. Water them in properly as soon as possible after application;
  11. If you are applying pre-emergents, you cannot seed for several weeks or months after application and finally
  12. It is much more difficult to control weed grasses in turf with post-emergent herbicides. So use pre emergents to prevent these becoming a problem.

 

FAQ

What is the best way to manage weeds in lawns?

The best way is to stop them growing in the first place. A healthy, thick and dense grass cover will stop weeds growing. Weeds are great opportunists so if the grass is weak and struggling to grow, there are thin patches or the soil is compact weeds will grow. 

If weeds still continue to be a problem then the using pre emergent herbicides is worth considering. These work by stopping weed seedlings from developing and vary in longevity from 10 weeks to 8 months. So basically you can apply once and have no weed issues for this length of time. 

Remember though, that you need to know what the weed is that you are trying to control as not all pre emergents work as well against all weeds.

Why is weed control important?

In agriculture weeds are a major problem as they dramatically reduce yields. In a turf situation we generally don’t deal in yield but weeds will limit turf growth by taking valuable nutrients and water away from the grass.

Weed control in couch lawns

The simplest way of controlling weeds is too hand pull them. However, in some cases weeds can be too widespread too effectively hand weed. Then I guess it depends if your trying to control grass or broadleaf weeds.
If the couch goes dormant (totally browns out over winter) then you can simply apply glyphosate and it will kill all the weeds no matter if grass or broadleaf. Adding a spray buffer or an appropriate spray adjuvant will guarantee the best possible results.
If your wanting to control weeds in couch when it’s growing then use a broadleaf post emergent herbicide is the way to go. If you want to stop them from becoming a problem use a pre emergent herbicide.

What can I use to kill weeds in my lawn without killing the grass?

The first option is too hand weed by simply pulling out the weeds. However, be aware that this can actually cause the problem to worsen I.e. nutgrass.
If the weed infestation is widespread then consider using a selective herbicide. Which one will depend on whether they are grass or broadleaf weeds and which particular weed.
Senior Turf Agronomist at Gilba Solutions Pty Ltd | Website | + posts

After Graduating from Newcastle University with an Hons Degree in Soil Science in 1988, Jerry then worked for the Sports Turf Research Institute (STRI) before emigrating to Australia in 1993.

He followed this by gaining a Grad Dip in Business Managment from UTS and has worked in a number of managment roles for companies as diverse as Samsung Australia, Arthur Yates and Paton Fertilizers.

He has always had a strong affinity with the Australian sports turf industry and as a result he established Gilba Solutions in 1993. Jerry has written over 100 articles and two books on a wide range of topics such as Turf Pesticides and Nutrition which have been published in Australia and overseas.