Mulching — the surface layer that changes everything

Mulch is any material spread on the soil surface. It suppresses weeds, conserves moisture, moderates soil temperature, and — if organic — feeds the soil as it breaks down. A 5 cm layer of good mulch applied in spring can halve your watering and weeding through summer. This is not optional fussiness; it is one of the highest-return tasks in the garden.

Organic mulches include compost, well-rotted manure, leaf mould, composted bark, and straw. Compost and manure feed as they mulch; bark and straw are longer-lasting but contribute little nutrition. Leaf mould — leaves rotted for one to two years — is the finest mulch for shrubs and perennials: it is weed-free, moisture-retentive, and improves soil structure as it disappears. Make it by stuffing fallen leaves into black bags, tying them shut, and forgetting them for a year.

Apply mulch when the soil is warm and moist — late April or early May in most of the UK. Mulching cold, wet soil in February locks in the cold and drowns roots. Pull mulch back from plant stems by 2–3 cm to prevent rot, and top it up each spring as it breaks down. On heavy clay, a gravel mulch around Mediterranean plants (lavender, cistus, rosemary) improves drainage at the collar and reflects light back onto the foliage.