Grevillea robusta – Silk Oak Tree Large-sized tree
This fast-growing evergreen tree will reach heights of forty feet or more with a twenty-thirty foot spread. It creates a tall silhouette with a mass of thick green fern like foliage. The underside of the leaves is grayish white in color. Golden orange, bottlebrush-type blooms form on the top of the tree in spring. Flowering occurs on mature trees after eight to ten years. A podlike fruit appears that opens to produce dark brown, winged seeds in late winter to early spring. If conditions are right, the seeds will germinate very easily. The flowers and seeds can be very toxic. The silk oak prefers full sun and can take reflected heat. Younger trees will do fine with filtered shade. This tree is drought resistant but prefers deep irrigation during the hot summer season. It does not like to be overwatered.
The silk oak is hardy to twenty-four degrees Fahrenheit. It does well in our sandy, desert soils, but prefers them to be well draining and slightly acidic. This tree is very disease resistant, but the branches are somewhat brittle and may break during high winds. It will produce some leaf litter in the spring when older foliage drops from the tree. Use the silk oak tree as a windbreak, shade tree, in parking lots, along roadways, or as an ornamental against a wall. This tree is native to the eastern coastal regions of Australia where it grows in subtropical rainforests. Its wood was valued for timber and used in furniture making. The silk oak has also been naturalized in Hawaii and Southern Florida.