This photo was taken at the entrance to Cranbourne Botanic Gardens. The soil is quite sandy and reflects the main need for all Banksias and that is very good drainage. This can be achieved by planting in a raised bed. I have read that the top of the planting hole only needs to be 4-6 inches (10-20cm) above the surrounding ground level to achieve the drainage required. The plant grows 2-4m wide and about 50cm high.
This is an adaptable drought hardy plant originating in Western Australia, north of Esperence. It will tolerate dappled shade through to full sun. It withstands light to moderate frosts.
This one uses Banksia coccinea as the feature flower. In the background is the grey -green foliage from Adenanthos serieus (Woolly Bush). Woolly Bush is the easier of the two plants to grow and they are quite drought tolerant. I have seen few good specimens of Banksia coccinea in South Australian gardens. I believe they are being grown in the Hills for the cut flower trade. The soil in that region is less alkaline and well drained. As a rule of thumb, Banksias will grow where there is excellent drainage even if the soil is alkaline.
The use of a mallee stump to form the arrangement makes this a truly unique Australian ‘picture’.
Todays’s jobs have been outside and included planting out a box of 24 Banksia plants in the front entrance area of our place. The spot was chosen for several reasons. Firstly these are spectacular plants when in flower so I wanted them to be where we could see them from the house. People driving or walking past would also get pleasure from the sight of the flowers. The area is well drained, deep, sandy loam, although inclined to be water repellant. Some of the plants will be quite large and will form a screen and windbreak which I want in that location.
Species planted were Banksia caleyi, praemorsa, marginata, sphaerocarpa, ashbyi, dryandroides, lemanniana, oblongifolia, repens, hookerana, candolleana. How successful they are remains to seen. The high pH of the soil may be a problem. I want to grow them without any external interference, other than water, if I can. I soaked the plants in a bucket of water containing a soil wettting agent. Tomorrow I will add some granular soil wetter to the planting spot just under where the dripper water will hit the ground.
More information on Growing Banksias