Most grevillea species that are available in nurseries root readily from semi-hardwood side shoots growing off one year old wood.
Usually take nodal cuttings by cutting at right angles immediately below a bud. They will also strike from basal cuttings (cutting through the base of the shoot where it joins the parent branch) as well as from heel cuttings (where a section of bark from the parent plant is pulled off with the cutting).
Many home gardeners have success with heel cuttings taken about 50-70mm.in length. They use a potting mix of one part sand to one part peat moss (or an environmentally-friendly substitute like coir), and then place them in a cold frame or plastic greenhouse with no bottom heat. It might be worthwhile experimenting with taking cuttings at different times of year if you attempt this.
