Australian garden design has seen a pretty big shift over the last decade away from those flimsy painted wooden stakes and tacky black plastic trim. Instead, people are opting for materials that break down nicely rather than looking like they’re in a sad state as soon as the weather changes. Corten garden edging is right at the forefront of this change, and there’s a lot more to it than just the warm rusty tones you see plastered all over the landscaping mags.
Understanding what Corten actually is, and how it behaves in a garden setting, explains things much better than a photo ever could.
What Is Corten Steel Anyway?
Corten, or weathering steel as some people call it, was originally developed for use in construction where it would be a real hassle to keep painting. The alloy is actually designed to form a stable oxide layer when it gets wet and then dries again. That oxide layer, the nice rust patina you see on the surface, acts as a kind of seal against corrosion. Conventional steel, on the other hand, just rusts away from the inside out because the rust layer is all porous and lets moisture seep in. Corten’s patina is different; it locks the steel in place.
That difference is really important when you’re talking about garden edging. Corten doesn’t need any painting, sealing or coating once the patina is formed. It’s not actually rusting in the classical sense, it’s just stabilising. The patina takes a good 2 3 years to fully develop in the Australian outdoors, going from bright orange to a nice dark brown. Places with a lot of moisture tend to see it settle in faster. Some suppliers in Melbourne now offer pre-rusted Corten edging, so you don’t have to wait for the patina to form before you can use it.
Why Is It Such A Great Fit for Australian Gardens?
Low maintenance isn’t just a luxury for Australians, it’s a basic necessity. People just don’t have the time to be constantly painting, replacing bits that have rotted or fixing damage from the sun. Corten edging takes that whole hassle factor right out of the equation.
And then there’s the aesthetic side of things. Australian native gardens are all about warm, earthy colours, think gravel, decomposed granite, eucalyptus bark etc. Corten fits right in with those colours because it’s got that beautiful rust patina which just looks so natural. It doesn’t clash with the garden at all, it just sorts of settles in with the rest of the colours. In a yard surrounded by green grey native foliage and red mulch, the Corten edging just blends in and looks like it’s always been there.
The Height, Gauge, and Practical Sizing
Corten edging comes in heights of 75 mm up to 200 mm. The decision regarding the height is dependent on what the edging needs to achieve. Low-profile edging of 75 to 100 mm is ideal for decoration purposes when the visual line is all that matters. On the other hand, the taller 150 to 200 mm is appropriate for use in garden beds where there are active grass runners invading or where soil retention is needed for structural purposes.
The thickness gauge, which can be either 1.5 mm or 2.0 mm, affects the stiffness of the material and how flexible it is. The heavier 2.0 mm gauge will hold its form under the stress exerted by the roots, movement of the soil, and people stepping on the material. The lighter 1.5 mm gauge will bend more easily by hand and is therefore better for curved garden bed edging designs.
Interlocking panels do not require external pins or joiners. The sections will fit together and hold their position even in the absence of external parts. This makes it simpler to install for both DIY garden enthusiasts and professional landscapers covering various gardens.
Alternatives to Corten Edging
While timber edging can be cheaper initially, it only lasts for a shorter period before it wears out in the soil. The presence of termites and the chances of rot make it necessary to replace this edging after only a couple of seasons. Plastic edging is inexpensive, but under UV rays exposure, especially in Australian summers, it cracks and fades easily making it unsuitable for garden edging.
Black galvanised powder-coated steel has similar properties to Corten steel except in terms of the colour. Black steel is the closest alternative and is suitable for gardens with a modern or contemporary style as compared to Corten.
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