Clay soil is composed of small particles that stick together very easily, leaving less room for air and preventing water from draining quickly. When wet, clay soil is very heavy to dig, and this density can make it hard for plant roots to find their way through. In the colder and wetter months, some plants in clay soil can be susceptible to rot.
It is often slow to warm up in spring, so plants are later to start into growth. During hot summers, clay soil can become extremely hard and may split into crevices. Summer rain may also run off the hard surface, rather than soak into the soil.
Clay soil needs less watering than chalky or sandy soils, and has plenty of nutrients available. This means that a wide range of plants can thrive, providing more options for garden designs.
How Do You Know if You Have Clay Soil?
Clay soil is made up of fine particles, and when moist it can be moulded by hand into smooth shapes rather easily.
If it becomes shiny when rubbed, it is classed as heavy clay soil.
Our Top Tips for Gardening on Heavy Clay Soil
- Clay soil can be acid, alkaline or neutral, so it is worth testing the pH with a kit.
- Improving clay soil is hard work but worthwhile. Dig it over in spring or autumn to break up any compaction. Dig in a large amount of organic matter to break up the clay particles, making the soil more aerated and less sticky.
- On established areas, add a layer of mulch 5-10cm deep every spring or autumn. This will conserve moisture in summer, reduce weeds and improve soil texture.
- Undertake planting from March to May and September to November, as this is when the soil is at its most workable.
- Avoid planting Mediterranean or drought-tolerant plants, as these will rot in poorly drained soil in winter.
- Break up the bottom and sides of planting holes with a garden fork.
- To prevent compaction, try not to walk or stand on the soil. Spread your weight by standing on a plank if necessary.
Our Top Plants for Clay Soils
Trees: Abies, Acer, Aesculus, Alnus, Amelanchier, Betula, Chamaecyparis, Cotoneaster, Crataegus, Eucalyptus, Ginkgo, Juniperus, Laburnum, Liquidamber, Magnolia, Malus, Picea, Pinus, Pyrus, Quercus, Salix, Sambucus, Sorbus, Taxus, Thuja
Bulbs, Corms and Rhizomes: Camassia, Crocosmia, Crocus, Erythronium, Galanthus (snowdrops), Hyacinthoides non-scripta (bluebells), Ipheion, Iris, Leucojum, Liatris, Lily
Climbers: Campsis, Chaenomeles, Hedera, Hydrangea petiolaris, Lonicera, Pyracantha
Shrubs: Abelia, Aucuba, Berberis, Buddleja, Buxus, Cercis, Chaenomeles, Choisya, Cornus, Corylus, Cotinus, Elaegnus, Escallonia, Euonymus, Forsythia, Fuchsia, Gaultheria, Hamamelis, Hebe, Hibiscus, Hydrangeas, Ilex, Kerria, Ligustrum, Mahonia, Nandina, Osmanthus, Philadelphus, Photinia, Pieris, Potentilla, Prunus, Pyracantha, Rhododendron, Ribes, Roses, Salix, Sarcococca
Ferns: Asplenium scolopendrium, Athyrium niponicum var. pictum, Blechnum spicant, Cyrtomium falcatum, Dryopteris erythrosora, Osmunda regalis, Polystichum
Grasses: Calamagrostis, Carex oshimensis, Fargesia, Miscanthus, Panicum
Perennials and Alpines: Actea, Ajuga, Alchemilla, Anemone, Aster, Astilbe, Astrantia, Bergenia, Brunnera, Canna, Convallaria, Dicentra, Digitalis, Echinacea, Euphorbia, Geranium (hardy varieties), Helenium, Helleborus, Hemerocallis, Hostas, Kniphofia, Lamium, Lysimachia, Monarda, Myosotis, Paeonia, Persicaria, Phlox, Polemonium, Rudbeckia, Schizostylis, Thalictrum, Tiarella, Trollius, Tulbaghia
Continue your Gardening Journey
Need a little extra advice? Visit your local Tates of Sussex Garden Centre today, where our friendly knowledgeable, team will be happy to help you choose the right plants and offer expert guidance.
