Gravel or bark mulch in a Mallorca garden?

Gravel for hot, exposed, windy positions and anywhere people walk. Bark or chipped prunings for beds where you want the soil to improve. Both cut evaporation sharply, which is the main reason either is worth laying: mulching reduces water loss from the soil surface by up to 70 per cent.

How they behave here

Gravel does not blow away, does not rot and reflects some heat back up into the planting, which suits Mediterranean species and punishes soft-leaved ones. Organic mulch breaks down over two or three years and feeds the soil as it goes, but it lifts in a strong tramuntana wind and needs topping up. On an exposed hillside, gravel. In a sheltered courtyard bed, bark.

The membrane question

Skip it under planting. Woven membrane under gravel sounds tidy and works for about two years, then wind-blown soil settles on top, weeds root in that layer, and the roots grow through the fabric so they cannot be pulled cleanly. Meanwhile the membrane blocks the exchange between mulch and soil that makes mulching worthwhile. Under a path or a driveway it earns its place. Under a bed it rarely does.

How deep

Enough to stop light reaching the soil. Around five centimetres of gravel or seven of bark is the usual guide, kept clear of plant stems so nothing sits wet against the collar. Thin mulch is decoration and does very little for evaporation.

What it costs

Mulching is normally part of a planting job rather than a line of its own, and planting with irrigation on a medium garden runs €7,800 to €11,200. As a retrofit into existing beds it is mostly material and labour, and it is the cheapest single change that reduces watering.

The planting that suits either surface is covered in the drought-tolerant garden guide, and the gravel garden as a lawn replacement in lawn alternatives. To have it done properly, send the job through.