Tree of the Week: The silk oak

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Good morning, Big Brown, it’s time to rise and shine and show the world what you’re made of. To the rest of you, welcome to another installment of Pieter Severynen’s ‘Tree of the Week.’

The silk oak – Grevillea robusta

‘Our trees here are even more cosmopolitan than our human population. Most of our Southland trees come from other parts of the world. Many stand out for their shape, flowers or foliage. Some sport a colorful history. By and large they are desirable neighbors, although some definitely have worn out their welcome. Several, including today’s silk oak, have both good and bad qualities, and should be used judiciously. All of them are fascinating.

‘Fast growing to 60 feet, sometimes 100 feet tall and 25 to 30 feet wide, the pyramidal- to oval-shaped silk oak easily towers above its surroundings. Often planted near roads, it really stands out in late spring when, especially in good years, clusters of showy golden yellow flowers almost completely cover the tree. A thick gray trunk, few but heavy branches, moderately dense crown, evergreen ferny leaves divided into many 2- to 4-inch-long leaflets, medium green above, silvery-gray below, make it easy to identify the tree when not in bloom. Small inconspicuous black fruits follow the flowers. The tree is beautiful in bloom, drought tolerant and useful as a fast and tall-growing hedge on a large lot. But it has enough undesirable characteristics to keep it away from the house: messy leaf, flower, branchlet and seed drop; brittle wood; branches that break easily. The tree benefits from guidance pruning in youth.

‘A member of the Protea family, which is known for unusual flower shapes, the silk oak comes from northern New South Wales and Southern Queensland, Australia. It is not related to oaks and does not produce silk. We use the tree only for its ornamental qualities, but in other parts of the world it is valued for its products. It provides medium-strength timber for furniture, plywood and guitar tops; plywood; and poles. In Eastern and Central Africa it is planted as a boundary hedge between farms which can be harvested occasionally for its wood, while the leaves provide mulch and cattle feed. The tree gives high shade and frost protection to coffee and tea shrubs in plantations. In warm and moist climates (Hawaii) it can become invasive.’

Thanks, as always, Pieter.
Your thoughts? Comments? Email story tip to peter.viles@latimes.com
Photo Credit: Pieter Severynen