There are two types of weeds, broad leafed weeds and narrow leafed weeds – grass weeds.
Broad leafed weeds are usually the main problem. These include the burrs, pig weeds, sensitive weed. Generally anything that is not a grass (a grass having a leaf that is basically the same width at the bottom and the top), is a broad leafed weed.
Purchase a broad leaf weedkiller from a garden shop. They may have different names but the active ingredients should be M.C.P.A. and Dicamba. Do not use a broad leaf weedkiller with Dicamba in it on Buffalo grasses. Make sure your grass weeds are growing well. This may mean fertilsing them a couple of weeks before spraying, mowing them 4 to 5 days before spraying, and watering them the day before you spray. Mix up spray to manufacturer’s recommendations, observing all safety procedures.
Generally, it is best to spray in the morning after the dew has gone and do not spray if rain is expected within 4 hours. You can spot spray the weeds or spray the whole area. Remember most of your garden plants are broad leaved so avoid spray drift.
Usually you will see weeds start to brown off in a week. Do not mow for a week after spraying.
Grass weeds are a bit harder to control but are generally not so unsightly in your lawn. The decision must be made whether to bother to get rid of them. In grasses like Tropika they do not stand out.
In hybrid/green couches i.e. Winter Green, Greenleas Park, Legend, you can buy sprays that will kill most grass weeds without affecting the lawn, but they are expensive and sometimes hard to source. These sprays have the active ingredients of M.S.M.A. or D.S.M.A. If you elect to go this way remember your lawn must be healthy to get a good kill. This spray will kill any Blue Couch, Tropika, Buffalo or Broad Leafed Carpet Grass in your lawn. It will kill nut grass but the underground nut will survive.
Some grass weeds are only annuals i.e. will grow, put up a seed head, then die. These may be the prevalent grass weed in some lawns that have suffered badly from the drought. To get rid of these weeds keep mowing and fertilizing to get your lawn thick and healthy so they cannot germinate next year.
Another way of getting out grass weeds is with a weed wand, or using rubber gloves and a rag damp with Round-Up (glyphosate) and rubbing this over undesirable grasses. Mix at 3 parts water to 1 part glyphosate. Remember this mixture will kill any plant so care should be taken, however if you do kill some of your lawn around the weed it is generally only 4 to 6 weeks and the lawn will cover that dead area.
The last way to get out weeds, and probably the cheapest, most efficient, and most environmentally friendly, is to pull them out. Get the whole family involved, may be some financial stimulus for the kids! Ideally wait for some wet weather and then get stuck in when the ground is soft.
Probably the worst weed around is nut grass. This can be controlled by repeated applications with the weed wand/rubber glove and rag treatment. There is now a product on the market called Sempra which will kill nut grass but it is extremely hard to get and not available at all in small quantities. It is very effective though and will not harm any lawn species. If nut grass is a big problem and driving you mad, call me, David Scott at Tanby Turf.
Grubs and Diseases
The main grub in the area is the Lawn Army Worm. This grub only affects lawns during the warmer months. Apart from areas of dying lawn, the main indicator of the presence of Army Worm is a red wasp with a long sting hovering over the lawn (these are predators of the army worm), birds (Ibis or Plovers pecking into the lawn), or a build-up of yellow cocoons on your house eaves.
To actually identify army worms either put a wet bag on the lawn in the evening then turn it over in the morning – any khaki coloured caterpillar-like grub is an army worm; or you can flood a small patch of your lawn and they will come to the surface. The decision must be made whether the army worm is doing real damage and should be controlled. Army worms are like fleas on a dog, if they are there you will probably never get rid of them completely. Certainly if you have laid down new turf you should spray as the army worm loves the new root shoots of new turf and can do great damage.
To control army worm at this stage the only effective way is with insecticides. Purchase a lawn grub killer from your garden shop. Follow all instructions and safety directions. It is very important to spray in the evening and quite often helps if insecticide is washed in with a light sprinkler.
It has been suggested that using a good dose of urea fertilizer will get rid of them. It will certainly knock them about but you will have to mow your lawn twice a week for the next three weeks. There is also some indication that crusher dust used as base for lawn may retard army worm.
The only disease of turf I have observed around the Capricorn Coast is ‘Spring Dead Spot’. This disease appears in autumn as small spots (approx. 50 cent piece) in your lawn. By early summer spots may join together like lattice work. By mid to late summer disease generally goes away. There are chemical controls of ‘Spring Dead Spot’ but they are not very effective. Usually good healthy lawn fed with organic fertilizer recovers quite quickly.
Fungal diseases are rarely noticed and their severity in a home lawn situation does not usually warrant treatment. Prevention is the better course and includes the use of organic or slow release fertilisers to encourage steady growth, and not watering during the evening or at night to prevent the build-up and maintaining of humidity and moisture at the plant base. Long thick lawns can also have a problem with high humidity and moisture at the plant base.