Growing native plants in Sydney

Soils and your garden

Knowing your soil type is an important step in helping you to select plants for your garden. Plants which are suited to your soil type will perform better – they will be healthier, more disease resistant and produce more fruit and flowers.

The two major soil types in the Sydney Region are sandy soils (derived from Hawkesbury sandstone) and clay soils (derived from shales or volcanic rocks). Some soils may be a combination of the two.

Some plant species will only grow well on one of these two soil types, while others are adaptable and will grow on both.

Improving your soil

Sandy soils are fast draining with good aeration but are usually low in nutrients. They can be improved by adding well-rotted organic matter such as animal manure, compost or leaf litter. They require fertiliser more often than clay soils.

Clay soils are slow draining, have poor aeration and are usually higher in nutrients than sandy soils. They can be improved by adding gypsum and well-rotted organic matter. Correct cultivation techniques will also assist in improving soil structure. However, if the soil is too wet or too dry when cultivated or is always cultivated to the same depth, drainage problems may arise.

Soil testing

There are a number of tests that can be done to determine soil type, pH (acidity/alkalinity), or the levels of nutrients in your soil. However, soil testing is not usually necessary for the home gardener and can be quite expensive.

If your garden is not flourishing there are many possible causes, including problems with watering, drainage, aspect and suitability of the plants selected. Further information can be obtained from horticultural reference books or from experienced nursery staff.

Visit the Gardening Australia site to watch host, Costa Georgiadis and the Australian Botanic Garden Mount Annan's Horticulturist, Stuart Elder chat about Australian native plants.