Lawn Rust – What causes it & Why – Not what you think

Lawn Rust isn’t the most common of diseases on grass. However, it can look unsightly if it appears on your lawn.

So, in this article I’m explaining when you would most likely see lawn rust occur, what it looks like and how to sort it out.

What, When & Why Does Lawn Rust Occur?

What is it & what does it look like

Rust is a disease that’s common in many plant species and grasses are no different. It’s slightly different to a yellowing of stems – often occurring due to lack of nitrogen.

It’s a much deeper brown/yellow colour and tends to form in concentrated areas of the grass

When does it occur?

The most likely time for lawn rust to occur is between late Summer and Winter. This is because grass is most stressed

What actually causes it

It’s caused by a specific fungi known as Puccinia or Uromyces species. These fungi are capable of paralyzing plants and grasses. Often for a short period.

While it’s difficult to say the exact cause, I do know that these fungi need a long time of surface water retention in order for them to infect the leaves of the grass and even other plants.

How long will it last and will it disappear if left untreated

How to treat lawn rust?

While there are no chemicals or fungicides you can use, you will find that it’s only a temporary issues. A bit like having mushrooms in the lawn. They’ll disappear after some time.

That said, if you remove water from the surface of your grass regularly, particularly during continuous wet days, you’ll likely see it gone much quicker and you should be able to prevent it altogether.

How to prevent lawn rust

Use the correct fertiliser at the right time of year

One key thing to know is the correct fertilisers to use. For example, using a high nitrogen fertiliser at the wrong time of year (Autumn & Winter) can make your grass more susceptible to diseases.

On the other hand, you should use high-nitrogen fertilisers during the growing season to keep the grass strong and thick.

I’ve written a full article called How to care for your lawn year round to help understand what feeds to use and when.

Don’t leave (long) lawn clippings on the grass after mowing

In some instances, leaving lawn clippings on the grass can be beneficial because of the nutrients it puts back into the soil. That said, if you are cutting a lot off the top and leaving it on the surface, it may become more susceptible to disease. Particularly if it’s wet.

Also note that if your grass is currently suffering from lawn rust, it’s better to collect the clippings in the mower box if you want to get rid of it sooner.

Improve air circulation above the grass