Spring Weeds

After a relatively wet and cold winter, weeds are out in full force this Spring. So what can you expect by way of weeds as the seasons change?

I found myself doing some maintenance around our display lawns this week and noticed how many weeds had recently germinated around me.  They seemed to be everywhere - in the brick pavers, the garden and, of course, the lawn. 

Weed activity in lawns during Spring:

In the coming weeks, you can expect weeds like winter grass and soursob to disappear by themselves without you having to do anything simply because they are annual weeds and only grow when soil temperatures are cold.  As soil temperatures rise, these weeds die down, disperse their seeds and lie in wait for next Winter. If you want to know more about controlling winter grass seed before it becomes a problem next Winter, Click here

In their place, you'll most likely see a new group of weeds emerge, and most of them will be broad-leaf weeds. It's not uncommon to see weeds explode at this time of year, and it can be quite disheartening to see them take over. 

Broad-leaf weeds are characterised by the presence of leaves as opposed to blades. They include:

• Clover
• Bur-medic
• Doc dandelion
• Creeping oxalis
• Bindie eye
• Chickweed  

And the list goes on. Some of these weeds are easy to control, such as dandelion and chic weed, and others are not, such as creeping oxalis, clover and bur-medic. 

How do you identify the weed types you have?

Sometimes it isn't easy to identify the exact type of weeds you have. Even if you know what they look like when they are mature, they often look quite different when they are juveniles. Fortunately, when it comes to controlling weeds in home lawns, it isn't as important to know the exact weed you have as it is to know the group it came from. This is because the selective herbicides you buy to control them will target a specific group rather than just one weed. 

How do you control weeds in the lawn?

Weed control can be approached using organic or chemical methods. For more information on organic methods, click through to my blog on chemical-free weed control. The alternative way, and the one I'll address in this blog, is by way of selective herbicides. There are many herbicides that will selectively control weeds in lawns. The type you choose and the methods you employ depend on the lawn you are spraying and the weeds you are targeting. Typically, there are herbicides for winter grasses, summer grasses and broad-leaf weeds, each of them registered to selectively kill weeds without killing your lawn. Since broadleaf weeds are prevalent now, these are the ones we'll focus on in this blog.

I'd say that one of the most important takeaways from this blog is that whether you choose to control broadleaf weeds organically or chemically, expect them to come back - quickly. It's one thing to control the weeds you can see, it's another to stop more from germinating. This is the difference between post-emergence control (controlling the weeds you can see) and pre-emergent control (controlling the weed seeds so that they don't come back)

Post-Emergent Chemical Control:

It is important to apply the right chemical. If you choose the wrong one, it won’t target the weeds you are trying to kill. Worse still, it may be toxic to the lawn variety you have. Some lawns (such as buffalo) are more sensitive to chemicals than others, so make sure you do your research.

In my opinion, one of the better chemicals (and less toxic ones) is called Bow and Arrow. It's safe for use on most lawns and does a great job on tough weeds like Creeping Oxalis and Clover. While it is expensive, it's effective. A secondary choice would be Amgrow Bin-die. Bin-die is good for most broadleaf weeds however, you may find you'll need to apply it more often when attacking invasive weeds like creeping oxalis, clover and medic.  

Do's:

• Always apply chemicals exactly as per the directions on the label. Avoid the temptation to make your spray mix stronger by adding extra concentrate.  It won’t make it work better and will most likely damage your lawn in the process.
• Apply a small amount of wetting agent to your mix just before putting the lid on your sprayer. This will help break the surface tension of the spray droplets, which will result in better contact with the leaf of the weed. It will also help stick the chemical on for longer. If you've had trouble killing weeds, wetting agents will supercharge your results. 

Dont's:

• Don't use hose-on type applicators - these are the ones that you click onto your hose. While this is easy and the chemicals in them will do the job, the method of application isn't ideal. There are too many variables regarding water pressure and flow coming through your hose, which can result in you either applying the chemical too diluted or too concentrated. It's far better to buy a concentrate and mix it up in a pressure sprayer. While it takes more time and effort, you'll get a more consistent result. 
• Don't use herbicides that contain Dicamba (and a lot do!). It’s a common ingredient in broad-leaf selective herbicides but can be very damaging to other plants and trees in your garden.

What if they simply won’t die?

We often hear of people who have used selective herbicides and gotten poor results. There can be many reasons for this. Following are some tips to ensure the best results:

• Ensure you have the right chemical for the job
• Make sure you apply the chemical at the right rate. Stronger is not better!
• Don’t apply when there is going to be rain or dew within 12 hours
• Pick a warmer day rather than a cold one
• Spray the whole lawn rather than spot-spraying – It’s easy to miss weeds when you spot-spray
• Be prepared to spray a number of times rather than just once, as there are many types of weeds that take a number of applications to achieve control. For example. mature weeds are harder to kill than seedling weeds, and creeping weeds (like creeping oxalis) are very persistent.   In these instances, a programmed and repetitive approach is required. Be prepared to spray 3-4 weekly until the weeds die. 

Pre-Emergent Chemical Control:

Some weeds are easy to kill, but they are hard to stop coming back. This is because weeds have a nasty habit of dropping their seeds into your soil. As you kill the weeds, more weed seeds germinate, making it look like you’re losing the battle. The solution to this is pre-emergent control. Once you have controlled the weeds you can see, you can apply a pre-emergent herbicide such as  Spartan. Spartan works to stop seeds from germinating and does a fantastic job at preventing re-infestation. 

As always, if you have any questions or problems you can't solve, give us a call on 8298 0555 or email us at info@paulmunnsinstantlawn.com.au