I found a photo of one of the Banksias to update this post. Banksia praemorsa is a good hardy plant which has a few different colour forms. My favourite is a wine coloured form which I do not see very often.
These Banksias seem to grow quite well in alkaline soils with good drainage. If plants seem unthrifty I try some agricultural sulphur, a cupful to the square metre, watered in because the soil here is highly alkaline. Failing that, some iron sulphate, or iron chelates (following packet directions). Good garden practice would see lots of organic matter going into the soil which would lower the pH a little over a period of time.
Banksias for difficult soil…
Banksia ashbyi
Banksia baueri
Banksia caleyi
Banksia coccinea (needs limestone subsoil)
Banksia ericifolia
Banksia grandis
Banksia integrifolia
Banksia marginata
Banksia media
Banksia ornata
Banksia praemorsa
Banksia prionotes
Banksia speciosa
Banksia victoriaeSome of these are in this list because of anecdotal evidence that they will grow in alkaline soil. More will probably be added as they are trialed by folk willing to have a try with the species.