Autumn weeds

Author: Stefan Palm   Date Posted: 7 April 2021 

Autumn, leading into Winter is a prime time for weeds to begin emerging in your lawn. With the extra moisture around and with less competition from Summer active lawns (as they go into Winter dormancy), weeds find the conditions irresistible.

As the weather cools down, weed seeds and bulbs stored in the soil from previous seasons germinate and grow, reminding you once again how persistent they can be! 

Now is about the time you'd expect weeds to surge however there is one element that has been missing so far this season, that being rain!  When it does eventually rain, I would expect the weeds will get going fairly quickly so my advice for now is to be prepared for when that happens.  Even in the course of general irrigation some weeds will already be germinating however it's not a bad idea to wait for another week or two before you start spraying so that you get as many as possible in the one go. 

The most common Autumn and Winter weeds are winter grass, sour sobs and of course, the common broad leaf weeds like thistle, dandelion, creeping oxalis, clover and bindi eye. Have a look at our handy Weed Identification Chart to see which type of weeds you have!

There are some things that encourage the likely hood of excessive weeds such as very low mowing, insufficient fertiliser and inadequate watering through the growing season. These conditions can weaken the stand resulting in any bare spaces which can quickly be colonised by weeds. Ineffective control measures in previous years can also lead to weed numbers increasing. They do this by flowering and dropping their seeds in the soil, ready to germinate when the conditions are right.

Most weeds in a lawn containing couch, buffalo or kikuyu grass are easily controlled by spraying with a selective herbicide. The type of herbicide you use will depend on the weed you are targeting.

Broadleaf Weeds:

For broad leaf weeds, use a product containing MCPA and Bromoxynil such as Yates Buffalo Pro. This sort of chemical is selective which means it is especially designed to be sprayed all over the lawn. It will target the weeds and will not effect the grass you are spraying. Generally speaking, broadleaf herbicides take around 10-14 days to kill the weeds. To get the best out of your herbicide, consider adding some wetting agent to the mix. Products like Wetter and Spreader help to break the surface tension of the spray droplets so that they get better coverage on the leaf of the weed. You'll be surprised at how much difference this makes.

Wintergrass:

Wintergrass is just starting to emerge now as the weather begins to cool down. Wintergrass can be controlled by using a herbicide containing propyzamide such as David Grays Winter Grass Killer. Follow the instructions carefully and make sure you spray evenly over the whole lawn area. Wintergrass killer is  a selective herbicide and is safe to use on couch and buffalo lawns.  As this chemical is soil activated, it is important that the sprayed area is watered within 24 hours of spraying. If you have wintergrass growing in kikuyu, then you can't use a propyzamide based chemical as a control measure. Your only option here is to wait till February and apply a pre-emergent herbicide such as Pendi Pro or Spartan which will kill the seeds of the wintergrass weed before they have a chance to germinate. Click here for more info on pre-emergent control of wintergrass. 

Once you know which types of weeds you have and what types of chemicals you intend to combat them with, have a think about your strategy. It's unlikely that you'll get rid of your weeds with one single spray, especially when it comes to broad leaf weeds. When tackling weeds like these, plan to spray every 3 to 4 weeks through Winter until they have disappeared.

To some degree, weeds will always be an uninvited guest in your lawn at different times of the year but with some vigilance, you can get on top of them. For more advice on controlling or identifying weeds, give us a call on 8298 0555. 


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