Bark chippings, also known as bark mulch, are a popular surface for play areas in gardens and woodland paths, because they blend in with the colours and textures of a natural landscaping scheme (see our article Surfaces for Children’s Play Areas on this site). But although bark can’t really be used as a surface for a heavily used drive, people are starting to use it for domestic driveways in areas where they want to maintain an eco-balance. This is because the chippings will biodegrade and don’t use many harmful products in manufacturing and laying, unlike other common driveway materials.
Pros and Cons of Bark Chippings
There are a number of advantages to using bark chippings. They are cheap, easy to lay and bind together under pressure from car tyres. They also absorb water, are soft underfoot and quiet. Of course, a surface that’s biodegradable is one that will need replacing or topping up quite often as it degrades, and that’s the main problem.
Older chunks of bark will decompose and the lighter ones may blow away, although pressing with a garden roller will help bed the mulch down. The absorption of water can cause a problem, too, because if you have too much of it, and the ground beneath the bark doesn’t drain properly, the area can get waterlogged and the bark will rot. That will cause it to break down even faster and smell nasty.
Preparing the Ground
So as long as the driveway area is well drained, laying bark chippings should be a doddle. There are two basic methods but preparing the ground will be the same regardless, and usually just involves removing the top layer of grass or other vegetation to prevent weeds breaking through.
You can lay a permeable membrane down over the site to help weed prevention but, if you’re using bark chippings as part of an eco-friendly landscaping project, you’re unlikely to want to unless it’s made from a natural material. Even if it is, then its manufacture will have left a carbon footprint, although laying old Hessian carpet underlay would be a good way of reusing a material that’s already left its footprint behind.
Laying Bark Driveways
The laying method you use will depend on the overall scheme of your landscaping project. It’s more usual to build borders up, perhaps from Timber Edging or similar material, so that the mulch layer will sit a couple of inches above the ground level. If you’re doing this for a playground, you should allow for at least a 30cm (12in) thick layer to help prevent injury from falls.
On footpaths, much less is required, perhaps 5-7cm (2-3in), and driveways should be somewhere in between. Too much and the cars will get bogged down, too little and the wheels will break through the driveway layer to the ground beneath, damaging the membrane if one was put down.
Natural Laying Method
The easier method is to simply lay down layers of bark chippings without the border. This might be better for a driveway as bark doesn’t give much support to any edging, so when vehicles drive over it, either by accident or to avoid something, they may break the border. Not having a border means that the mulch will spread further and break down faster, but after a few top-ups it should settle down.
The blurred edge that this will give you will just mean that the drive begins to blend in with the textures of the surrounding area, which will presumably be what an eco-friendly landscaping project will be trying to achieve anyway. And as it’s a completely organic material, it will help plant growth at the edges rather than hinder it.
Other Organic Driveway Materials
Of course, bark chippings aren’t the only organic loose material that you can use in a green landscaping project. Woodchips made from recycled, poor quality wood such as pallets can often be cheaper than bark. Because they are manufactured, you can get a more consistent size of chip, too. Although this might make the drive neater, you may also lose that effect of the blended textures, so the choice will depend on what you’re after.
You can also buy different sizes of wood chip, whereas with bark chippings you pretty much get what you’re given. Buying larger chips means they will be heavier than mulch and less likely to blow away, and the degradation process will be slower, so driveways will look neater and last longer.