Gravel gardens are a stylish alternative to conventional borders. They allow a wide range of ornamental yet tough plants to be grown, need relatively little maintenance and reduce the amount of watering required in summer.
British gardeners are becoming increasingly aware of the low-maintenance nature of gravel gardens, and their benefits are likely to make them more popular as gardeners meet the evolving demands of climate change. A gravelled area can replace an old, tired lawn or traditional border and impart a Mediterranean or alpine feel. Generally, gravel gardens are best in full sun as this favours most drought-tolerant plants.
A
true gravel garden is one situated on a predominantly gravely/sandy
soil, rather than simply planting on any soil mulched with
gravel. The poor soil conditions and sharp drainage limit
the range of plants that can be grown. Suitable plants for
a gravel garden are drought-tolerant, appreciating the free-draining,
relatively low-fertile soil which prevents the more vigorous
plants from becoming too lush and smothering some of the slower-growing
specimens.
General characteristics of drought-tolerant plants include adaptations of the foliage, such as a thick, waxy cuticle, numerous leaf hairs or narrow, strap-like leaves. Tap roots which can draw up deep soil moisture are another prominent distinction, as are hummock-forming growth habits. Many bulbous plants tolerate the dry summer period by laying dormant during this time.
Plants
The following selection of plants would be suitable for a gravel garden, as they are relatively drought-resistant and need little maintenance:
Bulbs
Allium
Colchicum
Crinum x powellii
Nerine bowdenii
Shrubs
Ceanothus
Cistus
Cordyline
Cytisus
Hebe
Hypericum
Juniperus
Lavandula
Rosmarinus
Salvia
Santolina
Thymus
Yucca
Herbaceous perennials
Achillea
Bergenia
Crambe
Crepis incana
Echinops
Eryngium
Euphorbia
Iris unguicularis
Kniphofia
Nepeta
Oenothera
Osteospermum
Papaver
Phlomis
Sedum
Verbascum
Grasses
Miscanthus
Pennisetum
Stipa
Bedding
Cosmos
Gazania
Portulaca
Climbers
Campsis
Trachelospermum
Planting
If the soil is low in nutrients it helps prevent more-vigorous plants from smothering slower-growing ones. If self-sown seedlings are not required, lay landscape fabric over the soil before planting and cut holes just large enough to take each rootball.
Small plants should sit proud of the ground so that gravel can be raked up to their crowns without swamping them. Do not plant too densely; leave plants room to spread and ensure some areas of gravel remain visible.
Thoroughly water in all new plants (and keep them watered in the first season after planting to ensure they establish well). Once planted, mulch the bed with 5-7.5cm (2-3in) of gravel or, even better, a layer of compost or straw covered with gravel which will retain moisture while plants establish.
Gravel
Different-sized gravel is available, graded by the size of the largest pieces: fine grades are 10mm or less, chunkier types are 20mm or more. Large-grade gravels, particularly if angular in shape, are easier to walk on than smaller grades or rounded pea shingle. If cats frequent the garden, larger grades will deter unwanted activities. Avoid limestone chippings if growing acid-loving plants.
A 25kg bag of gravel will cover 0.6sq m to a depth of 5cm. Gravel can also be bought in bulk, delivered by truck, usually in bags holding about 1 cu m, which should cover around 20sq m.
Gravel can be bought in a wide range of colours. Try to match the colour with other paved or stone structures in the garden. Local gravels will be cheapest.
Maintenance
Maintenance of a gravel garden involves mulching, weeding and pruning. A mulch of 5-7.5cm (2-3in) of gravel (or even better compost or straw covered with gravel) will retain a lot of valuable soil moisture while plants are establishing. Gravel levels can be topped up as and when required.
Weeding is most intensive in the first few years of establishment, before the ornamental plants develop. After this time removal of surplus self-seeded ornamentals is more likely.
Pruning mainly consists of removing spent flowers in the autumn or, if left for architectural effect, early spring.