In Queensland we have nowhere near the number of deciduous trees that our southern cousins have but that said, they are still around and can affect the health of our lawns.
Deciduous trees are those that annually drop their lawns during Autumn. Why are they a problem? While they do allow additional sunlight to reach your lawn plants during the cooler months, it’s the dropped leaves that are the issue.
Essentially, fallen leaves are nothing more the rotting plant material – they block sunlight to the grass underneath, hinder the oxygen, water and nutrients from getting where they need to go, and in turn make the lawn below more susceptible to fungal diseases and pests.
Luckily fixing this issue is fairly easily and not too time consuming. Rake up any fallen leaves and get them off the lawn – they can be added to your compost bin. If the leaves have been sitting for an extended period of time and the grass beneath is struggling, an application of fertiliser (remembering to water it in thoroughly) may be in order. If moss has taken hold below it will need to be removed by hand or with a specialty herbicide – never use a rake or similar to remove moss – it will just cause the spores to be spread further throughout your lawn.
If the idea of raking up the leaves from your deciduous tree is too much, there is another way. If you shred the leaves into small enough pieces with your mower then you can leave them on the lawn without fear that they will suffocate your lawn plants.
A mulching mower—one fitted with a blade that chops leaves and grass clippings into small pieces—does the job best, but a side-discharge mower also works. Set the mower height to 3 inches (7-8cms) and remove the bag. It’s best to shred leaves when you can still see some grass peeking through them, which means that you may need to pull out the mower more than once if you have big trees or a lot of the deciduous variety.
Begin mowing on the outside edge of your lawn, making sure that you shoot the leaves toward the middle of the backyard. Mowing in this way also allows you to mow over the leaves more than once. If the leaves are still in fairly large pieces after your first pass, go back over the lawn at a right angle to your first cut. Finely shredded leaves will now filter down through the grass and easily decompose by next spring.
If a thick layer of shredded leaves buries your lawn, you must suck up the extra leaves by making one more pass over the lawn with the mower’s bag attached. You can also mow with the bag on if you want to collect leaves for your compost pile, or to use as mulch in your garden beds. It’s best to have no more than a 1-inch (2.5cm) layer of leaf mulch on lawns. Mulched leaves return valuable micro-nutrients to your lawn, especially when mixed with grass clippings, and feed the microorganisms and worms that keep your soil and your turf strong and healthy. Contact the team at Harden Park Lawns to learn more about keeping your lawn healthy.
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