This is an easy-to-use weed ID chart that shows conditions favouring them and what herbicide products can be used for their successful control. More product information is available in our turf protection section.
Herbicides are classified in several ways:
- pre-emergent or post-emergent
- contact or systemic and lastly
- selective or nonselective.
Options
Pre-emergent herbicides are applied before weed emergence and act by killing weed seedlings as they germinate and try to emerge. In turf, they are mainly used against annual grass weeds such as Poa annua and summer grass, but there are also pre-emergent herbicides that are effective against many broadleaf weeds.
Post-emergent herbicides such as the sulfonylurea herbicides are applied after weeds have emerged and control actively growing weeds. These can be either contact or systemic.
Contact and selective herbicides
Contact herbicides cause localized injury where the chemical comes in contact with the plant and work best when applied to young weeds. Examples including diquat, carfentrazone, plant oils, and herbicidal soaps. In contrast, systemic herbicides move within the plant, causing injury at additional sites in the plant, and can control older weeds. Examples include glyphosate, quinclorac, triclopyr, or 2,4-D, dicamba, and mecoprop mixtures (an active ingredient in many broadleaf weed killers).
Selective herbicides kill target weeds without damaging desirable turfgrass species and are toxic to only certain plants or weeds. For example, 2,4-D selectively kills only broadleaf plants and not grasses. Nonselective herbicides kill all or most vegetation including turfgrass.
Weed ID Chart | |||
Bindii, Bindi-eye, Bin-dii | Bindweed | Black Medic | Buttercup oxalis, Wood sorrel, soursob |
 The weed is favoured by low light and excessive soil moisture. Chemical control best using one of 3-D, Casper, Monument, Contra M, Duke, Warhead. Can be an issue May to October. |  Loves compacted soils |  Favoured by drought, low fertility and compaction. Control best achieved using one of Casper, Monument, Contra M or Duke. |  Conditions that favour this are low calcium and drought, Chemical control best achieved using one of 3-D, Casper, Monument, Contra M, Duke, or Warhead. |
Capeweed | Carrot weed, Common cotula, annual buttonweed | Catsear, Flatweed, False Dandelion | Chickweed |
 Control best achieved by one of Contra M or Warhead. |  Chemical Control best achieved with Casper, Monument, Contra M, Duke |  Low fertility conditions favour this weed which can become a problem all year around. 3-D, Casper, Monument, Contra M, Duke, Warhead, |  Wet soil conditions, overly compacted soil and low light levels all favour this weed. Chemical control is best achieved using one of 3-D, Casper, Monument, Contra M or Duke. |
Crabgrass/summergrass | Creeping Mallow, marshmallow | Crowsfoot | Cudweed |
 Active from September to March when soil temperatures are between 12°C to 15°C for 14 continuous hours at a 10 cm depth below the soil surface. When temperatures are optimal, summer grass emerges 2 to 3 weeks earlier than crowsfoot. Post emergent control use Gauntlet or Quinstar and Preemergent control use Barricade, Battalia or Ronstar. |  Control using Contra M. |  Culturally favoured by poor soil fertility and wet, compacted soils. Can occur April to August. Post emergent options include Destro and Tribute whilst Barricade, Battalia and Specticle are excellent pre-emergent options. |  Can become a problem all year around. Best controlled using one of 3-D, Contra M, Duke, or Warhead. |
Dandelion | Flaxleaf Fleabane, asthma weed. | Flickweed, Hairy bittercress | Khakiweed,creeping chaffweed. |
 Compaction and low soil fertility favour this weed which tends to become a problem from May to August. Chemical control is best achieved using one of 3-D, Casper or Contra M. |  Can occur all year round. Chemical control best carried out using turf registered herbicides such as 3-D, Casper or Contra M. |  Commonly found in damp, recently disturbed soil. Occurs in two periods: February, March And April and then August, September and October |  Can be controlled with products containing dicamba such as Casper. Establishment occurs in warm conditions in spring and summer. |
Lambs Tongue, Ribwort, Narrow plantain. | Knotweed, wireweed | Nutgrass | Onion Grass, Guildford Grass |
 Favoured by low soil fertility, drought and acid soils. Can occur all year round. Chemical control can be achieved using one of 3-D, Casper, Contra M or Warhead. |  Appears August to March in droughty, compacted and acid soils. Post emergent options are Casper and Contra M. |  Prefers moist/wet soil with high soil fertility. Can occur from September to March. Post emergent control best achieved with Monument and Prosedge 750W. |  Guildford Grass can be treated using Duke herbicide. Its favoured by low fertility soil conditions. |
Paspalum, Dallisgrass | White clover | Winter grass (Poa annua) | |
 Favoured by wet, high fertility soils and generally becoming an issue from October through to February. Post emergent control can be achieved by using Gauntlet and/or Tribute. Barricade is also registered as a Pre-emergent preventative control option. |  This can occur all year round, being favoured by drought, compaction and low soil fertility. Chemical control is easy to achieve using one of 3-D, Casper, Monument, Contra M, Duke, or Quinstar. |  This can be regarded as the ultimate weed seemingly able to grow just about anywhere! Wet compacted soil, low light and low soil fertility can all favour this weed, with it generally making an appearance anytime between March to October. Post emergent control options include Monument, Duke, Checkpoint, Tribute, whilst Barricade, Battalia and Specticle can all be used as pre-emergent options. | |
Tips to get the best results when controlling weeds.
- Correctly identifying them;
- A weed is only a weed when it is present where you don’t want it;
- Cultural control should always be at the front of mind. Dealing with the conditions favouring a weed will stop it from occurring in the first place;
- Always read the label and respective MSDS sheet on any turf protection chemical you are intending to use.
- Ensure that whatever chemicals you use are safe to use on your turf;
- Spot treating is always a good first step. A good idea is to use a marker dye to see where you have treated;
- In some situations when the weed population is too high you are looking at a blanket application;
- A selective post-emergent herbicide works best when weeds are actively growing. For example, applying a post-emergent herbicide in drought conditions will generally be unsuccessful;
- Certain post-emergent broadleaf herbicides, such as dicamba, can be absorbed by tree roots and may cause tree injury if applied too close to the tree drip line;
- The key to success for all pre-emergent herbicides is to apply the herbicide 2 to 3 weeks before weed germination;
- Pre-emergent herbicides work best when the soil is moist but the turf is dry at the time of application. They should also be thoroughly watered in as soon as possible after application;
- If you are applying pre-emergent herbicides, you cannot reseed for several weeks or months after application and finally
- It is much more difficult to control weedy grasses growing in turf with post-emergent herbicides.