How to Garden in Clay Soil
Planting in clay soil
We're often asked how to manage clay soil and which plants work best, so we've put together a handy guide to improving your soil and a list of plants best suited to clay. Plants struggle to thrive in clay soil due to the density of its fine particles - roots have to work extra hard to establish themselves. When plants do thrive, they find that clay is often an excellent growing medium.
How to tell if your soil is clay
Grab a handful and squeeze it.
Wet clay soil is quite sticky and pliable, it takes a long time to dry out, and forms lumps.
Dry clay soil is almost rock hard and impossible to get a shovel into, except in the large cracks that often appear.
The plus side to clay soil is that it's loaded with nutrients! Improve the soil structure, choose plants suited to clay soil, and watch your garden thrive.
Ways to improve the quality of clay soil
- The simplest and most effective method is to dig organic matter through the soil. It not only adds nutrients but also binds to the soil improving drainage while retaining moisture during dry spells.
- Adding natural powdered Gypsum to the soil changes its structure and the soil becomes fine and crumbly. We recommend adding organic matter to improve its effectiveness.
- Another great clay-breaker is eco-flow gypsum. Available in an easy hose-on application that includes a boost of eco-seaweed. As the product is liquid it's more readily available to plant roots than the dry powdered form.
Again, the addition of organic matter will help to get the most out of this product.
Quick tips for planting in clay soil
- Avoid planting when the soil is excessively wet or dry
- Dig a hole that is at least three times the size of the root ball of the plant
- Add some well composted organic matter and turn with a garden fork
- Place the plant in the centre and back fill, taking care not to plant too deeply
- Check regularly and water as required until the plant is established, usually around 12 weeks
- Apply a good layer of mulch during the dry season to help retain moisture
Top plants for clay soilWant to ditch the shovel and plant a garden? There's a surprising range of plants suited to clay soil, from groundcovers to feature trees. Many native plants are ideal, they're naturally exposed to prolonged periods of rain followed by drought.
Ground coversBrachyscome (cut-leaf daisy) and Scaveola (fan flower) are perfect for a sunny location and feature masses of flowers spring and summer. For a shady spot try native violets. Bauhinia corymbosa (orchid vine) grows happily in dense soil and is super hardy, with loads of pink-orchid like flowers. Grevillea lanigera, also known as woolly grevillea; and grevilea Royal Mantle love exposed sunny sites. Plant to control weeds and prevent erosion on hard to reach embankments.
GrassesDianella (flax lily) are compact growing native grasses suited to shady locations, perfect for borders and under-planting. Lomandra, Festuca glauca (blue fescue) and Ficinia (knobby club rush) are tough grasses and can tolerate both wet and dry conditions, and full sun.
Small ShrubsCallistemons absolutely thrive in clay soil and burst to life with bottle brush flowers spring and summer. Lower growing varieties include Captain Cook, Rose Opal and Tangerine Dream. Formal borders and hedges can be created using Westringia (coastal rosemary). Westringia are hardy, low maintenance plants suited to dry climates. Available in low growing forms suited to borders are Aussie Box® & GREY BOX™. For taller hedges try Wynyabbie Gem or Westringia fruticosa, the species form. Leptospermum (tea trees) are low growing natives featuring clusters of tiny flowers in shades of white to deep pink. Suited to dry areas in full sun. For cottage style gardens plant lush growing hydrangeas in shaded areas and roses and buddleia in sunny locations.
Large shrubsBanksia and Grevillea species prefer dry soil, so if you live in an area with low rainfall, these shrubs are ideal. Plant as a feature or screening tree. Plant Viburnum for evergreen hedges, roses for colour, and for a rambling cottage feel, white flowering spiraea (May bush).
TreesPlant larger growing callistemon varieties like King's Park Special, Dawson River Weeper and Candy Pink for dappled shade and bright flowering colour. Hymenosporum (native frangipani) are tall feature trees bearing scented creamy-yellow flowers, suited to full sun and partly shaded locations. Thuja (Western red cedar) makes an ideal screening conifer for larger gardens and formal entrances. Lagerstroemia (crepe myrtle) are a great choice for gardeners looking to add flowering colour.
ClimbersPandorea varieties perform really well in clay soil and once established will tolerate prolonged dry periods. Climbing banksiae roses will grow happily in clay.
You'll find a full selection of plants for clay soil in our Plants for Problem Places - Clay Soil category.