Always choose healthy well grown plants and plant after autumn rains planting then when the soil is moist and warm allows the plants to become established before winter. This enables them to withstand dry periods during the following summer. Planting success is often improved on clay soils by adding extra topsoil and forming raised beds. Incorporate coarse sand, bark, compost or other organic material to improve soil structure. Before planting ensure that the root-ball is saturated and remove planter bag pot or wrapping with the minimum of root disturbance. Trim any broken roots and plant at the same level as in the container. Dig a hole twice the diameter of the root ball and firm in and water once planted. Make sure plants are watered well until established if planting in a drier period. Plant with some general slow release fertiliser and then every spring apply an organic based fertiliser such as blood and bone at a handful per square metre as new growth begins.
Shady areas often have dry soil due to overhanging canopies or structures and because of root competition from trees. It may be necessary to irrigate new plantings and occasionally mature plantings during droughts. When adding organic matter to soils beneath mature trees, it is best to apply it as a layer above the soil rather than working it in and disturbing the tree roots. This also makes planting far easier and helps to retain moisture in the soil.
Planting too closely leads to spindly growth, poor flowering and eventual decline. In a well-planned border, the plants in flower should just touch each other to create a full effect without overcrowding. Plant approximately 50cm apart.