Gardens as fire defence

Gardens serve many purposes – decoration, food production, and even status symbols. But gardens can be so much more. Depending on what – and how – you plant, your garden can increase or decrease your risk of fire (and many other things, but let’s stick with fire).

Zones of safety

Whether you are designing a large-scale landscape from scratch for a greenfield development, maintaining an existing estate, or planning a small domestic garden, you will almost certainly divide up your space into different sections. So, when you do, keep in mind how fire spreads. It’s a good idea to have something relatively fire-resistant on the periphery – like a line of fire-resistant indigenous forest trees such as Cape beech (Rapanea melanophloeos), rooiels (Cunonia capensis), milkwoods (Mimusops sp.) or yellowwoods (Podocarpus sp.). Or you could plant a hedge of num num (Carissa bispinosa).

And some open ground that can form a firebreak is also handy. If you have sufficient water, this could be a lawn (but please be careful which grasses you plant) or it could be a section of paving or gravel. If you do decide on paving, please opt for something permeable. Of course, a lap pool, moat or ‘fire pool’ is also a great idea, but you need to balance this out with the need to conserve water.

Closer to the house, be careful not to plant anything too flammable right up against the house – especially creepers. Some of these, such as ornamental vines and Virginia creepers, lose all their leaves in winter, and can be a fire hazard, especially in the summer-rainfall areas.

Be careful to leave spaces between plants, or to intersperse succulents with more ‘flammable’ plant types.

Types of plants

Mature trees, such as those discussed above, are usually quite resistant to fire, but all trees are not equal. Alien trees like pines and eucalyptus are particularly fire-prone, and tend to burn explosively, sending burning particles hundreds of metres away. Almost all the recent bad wildfires have involved one or both of these trees – eucalyptus in Australia, pines in California, and both along the Garden Route and in Cape Town. If you are developing or managing a piece of land with pines or eucalyptus trees, seriously consider replacing them with indigenous forest trees.

Succulents, such as aloes and vygies – and especially sour figs (Carpobrotus edulis) – are particularly fire-resistant. And, of course, the increasingly popular spekboom (Portulacaria afra) makes great hedges, but bear in mind that while you want to keep the leaf litter around for carbon sequestration purposes, it’s best to tidy it up for fire-retardation purposes.

Frills and fripperies and general housekeeping

It’s not just plants; consider garden structures such as fences, decks, trellises, and also garden decor. Wooden ‘latte’, for example, are very pretty – but also, once they are a few months old, very flammable. Wooden trellises against houses may facilitate the spread of a fire, and consider carefully the potential of every piece of garden decor to either spread or retard a fire. A series of colourful banners, similar to Tibetan prayer flags, are a beautiful addition to many gardens, but thin fabric is notoriously flammable, and delicate bamboo structures or wind chimes may also ignite if a spark lands on them. And we all know a thatched boma looks lovely and makes for fabulous garden lunches, but a thatch roof is – in effect – just a very tidy pile of tinder. And, of course, dry leaves should be raked up regularly, and any dead foliage trimmed and discarded.

Composting is a great idea for many reasons but it does need to be done carefully. The chances of a domestic compost heap catching fire are extremely low, but community-level large-scale compost systems can spontaneously combust if they are not managed well and turned regularly. (This is also very unlikely, but the small possibility of its happening is a reminder to estate managers and/or service providers to very carefully manage compost.)

Even beautiful hanging ornaments like sun catchers can be a fire risk. I was once sitting at my desk on a sunny day, deeply absorbed in my work, when I noticed a subtle movement out of the corner of my eye. And then I smelled burning, and, as I turned, I saw a thin plume of smoke rising from a dark spot on a piece of paper on my desk. I moved the red-hot document out of the concentrated spot of light, and then traced it back to a beautiful glass paperweight I had carelessly left on the windowsill. (We’ve all played that game with a magnifying glass as kids.) This can happen with glass jars, and even with plastic balls.

So the take-home lesson is that, despite the fact that it can be so hard to start a braai fire, fires can start – and spread – very easily.