Planting in Gravel

Gravel is an adaptable material that has many practical advantages in the garden. It can protect drought-loving plants from suffering in wet climates, re-create desert or alpine conditions, and even offer a solution for coping with desperately dry soils.

As ground-covering mulch, gravel can be used in a number of imaginative ways to create specialized habitats for plants that naturally grow in dry surroundings. Many of these, especially rock and alpine plants, and Mediterranean species, resent water lying where their stems meet the roots, and have difficulty surviving a wet winter unless provided with very efficient drainage. A gravel mulch allows water to drain fast and, when laid over a geotextile membrane, it also helps plants to survive hot dry summers by keeping their roots cool and moist.

Creating a Gravel Bed

If your soil drains well, start by digging and removing the topsoil to a depth of about 8 cm (3 in), and take out any weeds. If the soil is very dry fork in some leaf-mold or garden compost. Replace the topsoil with 5cm (2 in) unwashed gravel, and tread firm to consolidate the finer particles. Finish with a 2-3 cm (1 in) layer of shingle or 'pea gravel', which also needs rolling or treading.

Heavy clay or wet ground needs deeper preparation. Dig out the topsoil to a full spade's depth, and loosen the exposed subsoil with a fork. Then spread a 15 cm (6 in) layer of rubble, broken bricks or similar hardcore, and tread or ram firm. Cover this with a layer of inverted turves or plastic sheeting well perforated with a fork for drainage. Infill the bed with a free-draining planting mixture, tread firm and top up if necessary, but leave space for the 2-5 cm (1-2 in) gravel mulch.

Planting in Gravel Beds

To make planting pockets in a deep gravel bed you will need a crowbar, or strong metal rod, as well as a trowel.

• Scrape the gravel to one side; drive the crowbar through the base layer and stir it round to enlarge the hole.
• Fill the hole with planting mixture (see above) and firm with your fingers.
• Make a hole in the mixture with a trowel, a little larger than the rootball, and position the plant so that the top of the rootball is level with the surface.
• Fill round the rootball with planting mixture and firm gently. Replace the gravel round the plant stem, level and water well. You may need to water the plant again in dry weather until new growth is visible.
  caring for gravel gardens.
• Raking will roughly level gravel and shingle, but a more uniform finish can be obtained by scraping across the gravel surface with the edge of a flat wooden board.
• Clear autumn leaves and other plant debris from a gravel garden before it decomposes. Lightly brush it off with a stiff broom, or use a powered leaf blower.
• Top up bare patches with fresh gravel in autumn and spring, especially around the base of plants, and re-level the surface with a rake or a board.
• Pull up weeds as soon as you see them. Do not allow them to become established.

Gravel-Planting Tips

• Do not use limestone chippings around acid-loving plants, which will react to the presence of lime with poor growth and leaves turning yellow.
• On steep slopes use ground-cover plants such as bugle (Ajuga reptans) or creeping jenny (Lysimachia nummularia) to help stabilize the gravel and prevent it from creeping downhill.
• Lift and divide mat-forming and other spreading perennials every few years to keep them young and vigorous. After replanting, water them in with a diluted liquid feed and mulch with fresh gravel.