How to recover your lawn after cyclone narelle

How to Recover Your Perth Lawn After Cyclone Narelle - Lawn Doctor
Perth Lawn Alert · Autumn 2026

How to Recover Your Lawn
After Cyclone Narelle

By Lawn Doctor Turf Solutions  ·  March 2026  ·  Perth, WA

If your lawn is looking worse for wear right now, you're not alone. As Ex-Tropical Cyclone Narelle tracked south along the WA coast last week, Perth and the surrounding suburbs copped significant rainfall - in some areas, more than 50–100mm fell in under 48 hours. For a city built on sandy coastal soils that drain quickly under normal conditions, that kind of sustained downpour creates a different set of problems than you might expect.

The good news is that Perth's sandy soils are actually well suited to recovery - once you know how to work with them. Here's what you need to do, in the right order.

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Safety first
If water is still pooling or flowing across your property, wait. Make sure all hazards have been identified and the ground is stable before you start working on your lawn. No recovery task is worth putting yourself at risk.
Waterlogged Perth lawn after heavy rainfall from Cyclone Narelle
Heavy rainfall from Ex-Tropical Cyclone Narelle left many Perth lawns saturated - but recovery is possible with the right steps.

Why Perth Lawns Behave Differently After Heavy Rain

Most lawn care advice after flooding is written for heavier clay-based soils common in eastern states. Perth is different. Our soils are predominantly white sand - highly porous under normal conditions, which is why we need to water so often in summer. But there's a catch: that same sandy soil is prone to becoming hydrophobic.

When sandy soil dries out repeatedly over our hot summers, organic particles in the soil develop a waxy coating that actually repels water. During a rainfall event like Narelle - where large volumes of rain fall faster than the soil can absorb it - water sits on the surface and runs off rather than penetrating to the root zone. The result is that your lawn can look waterlogged on top while the roots are still dry underneath. It's counterintuitive, but it happens regularly in Perth gardens after intense rain events.

The other issue unique to our soils is nutrient loss. Sandy soils have almost no capacity to hold nutrients - they leach straight through. A sustained rainfall event will have flushed a significant amount of soluble nitrogen and potassium out of your lawn's root zone, which you'll need to replace once conditions settle.

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Perth Soil Fact
Perth's Spearwood and Bassendean sands are some of the most nutrient-poor, hydrophobic soils in Australia. This is why commercial-grade wetting agents and slow-release fertilisers make such a big difference here compared to anywhere else in the country.

Step-by-Step: Getting Your Lawn Back on Track

1
Clear debris and let it breathe
Remove any leaf litter, garden debris, or sediment that has washed across your lawn. Anything blocking direct sunlight to the grass blades will slow recovery significantly. Use a rotary mower with a catcher - it's surprisingly effective at picking up light debris without damaging the turf.
2
Test for hydrophobic soil - then treat it
Pour a small amount of water onto a dry-looking patch. If it beads up or pools rather than soaking in within 30 seconds, your soil is hydrophobic. This is extremely common in Perth after any weather event that causes a wet-then-dry cycle. A quality wetting agent is essential - not optional.
Step 2 - Recommended Wetting Agents
Soil Soak Wetting Agent 💦 Liquid
Soil Soak Wetting Agent
A fast-acting liquid wetting agent that penetrates Perth's hydrophobic sandy soils quickly. Apply via hose-on or sprayer. Ideal as an immediate post-rain treatment to restore water penetration and get moisture back to the root zone.
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Knights Wetta 💦 Liquid
Knights Wetta
A commercial-grade liquid wetting agent designed for ongoing soil maintenance. Apply every 8 weeks through the recovery period and beyond to keep Perth's sandy soils penetrable and prevent dry patch from returning.
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3
Aerate to restore oxygen to the roots
Even sandy soil can compact under sustained rainfall. A garden fork pushed 10–15cm into the lawn every 15–20cm across affected areas will allow oxygen back into the root zone, help break up any surface crust, and improve drainage. Do this a few days after the rain has eased, once the surface has firmed up slightly.
4
Watch for fungal disease
Warm, wet, humid conditions after a cyclonic event are exactly the right environment for turf disease to develop. Look for brown or yellow patches, slimy grass blades, or a rust-coloured residue on your shoes after walking the lawn. If you catch it early, aeration alone may resolve it - if symptoms persist after a week of dry weather, a fungicide application will be needed.
Step 4 - Recommended Fungicides
Chlortan 720 Fungicide 🍄 Contact
Chlortan 720 Fungicide
A broad-spectrum contact fungicide effective against a wide range of common turf diseases including brown patch, dollar spot and leaf spot. A reliable first response when disease symptoms appear after wet conditions.
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Heritage Maxx Systemic Fungicide 🍄 Systemic
Heritage Maxx Systemic Fungicide
A systemic fungicide that moves through the plant to protect new growth as well as treating existing disease. Longer residual activity than contact fungicides - ideal where disease pressure is high or conditions are likely to remain humid.
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5
Get mowing again as soon as it's dry enough
Mowing encourages lateral growth and recovery. Don't wait for the lawn to look perfect - mow at your normal height as soon as conditions allow. If the lawn grew significantly during the wet period, don't take it all off at once. Drop the height one notch, wait a few days, then return to your normal setting.
6
Fertilise once recovery is underway
Wait until you can see active new growth before reaching for fertiliser. Applying product to a stressed or waterlogged lawn is money down the drain - literally, in Perth's sandy soils. Once the lawn is clearly recovering, a good fertilise will significantly accelerate the process and help replace the nutrients that leached out during the rainfall event.
Step 6 - Recommended Fertilisers
Knights Coastal Special Lawn Mix 🔅 Granular
Knights Coastal Special Lawn Mix
Formulated specifically for Perth's coastal sandy soils. Replenishes the nitrogen and potassium leached out during Narelle's rainfall and builds root health heading into winter.
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Exceed Liquid Fertiliser 💦 Liquid
Exceed Liquid Fertiliser
A liquid fertiliser option for fast uptake - even if root systems are still recovering, the leaf can absorb and distribute nutrients immediately. Ideal for jump-starting recovery where the lawn is showing signs of new growth but needs a nutrient boost.
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7
Apply a pre-emergent herbicide
This is a step most Perth homeowners will miss, but it's important. Heavy rainfall events wash in weed seeds from neighbouring properties, drains and roadways. Applying a pre-emergent herbicide once your lawn has stabilised will stop that second problem - an explosion of winter weeds - before it starts. Timing is everything: apply before the seeds germinate, not after.
Step 7 - Recommended Pre-Emergent
OxaFert Pre-Emergent and Fertiliser 🔅 Granular · Pre-Emergent + Fertiliser
OxaFert
Two jobs in one application - stops winter weed seeds germinating while giving your recovering lawn a fertiliser boost. Ideal for use once your lawn has stabilised after the wet period. The weed seed load washed in during Narelle will be significant - don't skip this step.
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What About Waterlogging? Sandy Soils Drain Fast - But Not Always

One of Perth's advantages after an event like Narelle is that our sandy soils drain significantly faster than the clay soils in other parts of Australia. In most cases, surface pooling should clear within 24–48 hours of rain easing. If water is still sitting on your lawn three or more days later, you have a drainage issue that pre-dates Narelle and will need to be addressed separately - either through aeration, grading, or installing subsurface drainage.

If your lawn drains quickly but the grass still looks poor - pale, limp or straw-like - the problem is almost certainly hydrophobicity or nutrient depletion rather than waterlogging. This is where Perth gardeners need to think differently from the advice written for other states.

The Armyworm Risk After Narelle

One threat that's easy to overlook in the post-storm recovery period is armyworm. Cyclonic rainfall events and the warm, humid conditions that follow create ideal breeding conditions. Armyworm caterpillars feed at night and can strip a lawn bare surprisingly quickly - you often don't notice the damage until a large patch has already gone.

The soapy water test is the quickest way to check: mix a bucket of soapy water and pour it over a 30cm square of lawn. If armyworm is present, the larvae will surface within a few minutes. Check several spots across the lawn, particularly in sheltered areas that stayed moist during the rain.

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Pest Identifier
Not sure what you're looking at? Use our free Pest Identifier tool to diagnose common Perth lawn pests and get the right treatment recommendation for your turf variety.

How Each Variety Is Likely to Handle the Recovery

Sir Walter Buffalo

Sir Walter is one of the more resilient varieties in wet conditions due to its broader leaf blade and strong lateral growth habit. It will recover well once it can get sunlight back to the leaf and the soil moisture normalises. Watch for fungal disease particularly in shaded areas, as Buffalo holds moisture longer than couch varieties.

TifTuf Hybrid Couch

TifTuf's deep root system - one of its key strengths in drought conditions - also helps it access drier soil below a waterlogged surface layer. It can look worse before it looks better, as it goes semi-dormant under sustained stress. Get it mowing again as soon as possible to stimulate lateral growth and recovery.

Zoysia Australis

Zoysia is a slower-growing variety under normal conditions, which means recovery will be more gradual. The upside is that its dense, fine-textured canopy is relatively resistant to weed invasion - but you should still apply a pre-emergent once conditions settle, as the seeds washed in during Narelle will still be in the profile waiting to germinate.

Nullarbor Couch

Nullarbor Couch is well suited to Perth's conditions and handles wet-dry cycles better than many varieties. Like TifTuf, getting back into regular mowing is the single most effective thing you can do to stimulate recovery. Focus on the wetting agent and fertilise steps once you can see new growth.

The Short Version

Perth lawns after Narelle face two main challenges that are specific to our conditions: hydrophobic soil that looks saturated but won't absorb future water properly, and nutrient-depleted sandy soil that needs replenishment once the lawn is visibly recovering. The steps above address both, in the right order.

Don't rush to fertilise or apply any product to a stressed lawn - the timing matters as much as the product itself. And don't skip the pre-emergent step. The weed seed load washed in during last week's rainfall will be significant, and getting ahead of it now will save you a lot of work through winter.

If you're not sure what your lawn needs or which products are right for your variety, give us a call or come in to see us at Wangara - we've been looking after Perth lawns for over 50 years and we know exactly what works on our soils.

We're here to help

Need advice on your
post-Narelle recovery?

Call us, email us, or browse our lawn care shop for all the products mentioned in this guide - including wetting agents, pre-emergents, fertilisers and pest treatments suited to Perth conditions.

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