The deciduous good-looking Silk Oak, scientifically often known as Grevillea robusta (grev-ILL-ee-uh, roh-BUS-tuh) is part of the household Proteaceae.
It’s native to the temperate local weather of jap coastal Australia (Queensland and New South Wales), thriving in riverine, subtropical and dry rainforest environments.
It has grow to be naturalized in lots of locations, together with on the Atherton Tableland in Australia and in South Africa, New Zealand, Hawaii, French Polynesia, Norfolk Island (house to Norfolk Island Pine), Jamaica, and Florida.
Inside its genus, the Silk Oak is the most important tree.
Its alternatively-arranged fern-like foliage could be very stately, making it good for decorative gardening.
Additionally, you will discover the tree lining streets in its native vary, making a exceptional skyline silhouette.
You may additionally hear it referred to as by its frequent names together with:
Southern Silky Oak
Australian Silver Oak
Grevillea Robusta Care
Measurement & Development
Silk Oaks are majestically good-looking bushes succeeding and flower in temperate or tropical climates.
The actual species is a quick progress price evergreen tree reaching as much as unimaginable heights between 20’ – 100’ ft.
The trunk is straight, and unbuttressed, and is 31” – 47” inch in diameter.
When planted in tropical areas, the tree can develop at elevations from 40’ ft to 8000 ft and from sea-level to ½ mile in temperate climates.
Flowering and Perfume
Silk Oaks are evergreen and in leaf all year long.
They flower for just a few weeks in October and November however solely when the rising circumstances are proper.
In lowland tropics, flowering is poor or doesn’t happen in any respect.
Silk Oak showy golden orange flowers are one-sided racemes and seem in teams.
They’re typically branched and 5” – 6” inches lengthy.
These flowers are wealthy in nectar and entice bees in giant portions.
Nevertheless, in the event you’re rising a Silk Oak from darkish brown seeds, it’ll solely flower when it’s about six years outdated.
Mild & Temperature
Silk Oaks are hardy to USDA hardiness zones 9 to 11.
As soon as the tree is established, it may well tolerate temperatures all the way down to 18° levels Fahrenheit (-Eight° C).
Nevertheless, the vegetation develop greatest and like heat temperate climates.
The bushes love full solar however can develop in semi-shade or mild woodland environments.
Select a location getting no less than six hours of daylight within the day.
Be cautious about extended publicity from the western solar as it may well trigger trunk sun-scald.
Watering and Feeding
Silk Oaks have common watering wants and are appropriate for xeriscaping.
Nevertheless, their roots are inclined to root rot and different fungal ailments brought on by overwatering.
So ensure that to make use of a good-draining soil and don’t drown the roots.
Though the tree is drought resistant and may reach dry soils, they do their greatest and usually tend to flower in moist, barely acidic soil.
As for feeding, they love pretty excessive fertility.
Soil & Transplanting
The Silk Oaktree doesn’t reply too nicely to dry websites.
They thrive in well-draining soil which doesn’t let water stand too lengthy across the roots.
Supplied this requirement is fulfilled, the tree will develop in sandy, loamy, and clay soils.
As for the pH, they like barely acidic to impartial soils.
If you’re beginning seeds inside or in containers, they’re transplanted of their everlasting places as soon as they’re Eight” – 12” inches tall.
This takes in all probability 6 to eight months following the seed sowing.
As soon as transplanted, they may want shade for the primary 2 or three weeks for it to ascertain additional.
Grooming and Upkeep
Prune the tree as wanted because it helps elevate the foliar cover additional.
Pollarding is carried out repeatedly to yield wooden and regulate shading.
The Silk Oak is powerful and doesn’t want an excessive amount of upkeep.
Therefore, it’s typically used as a road tree.
The Silk Oak has sometimes prompted contact dermatitis following contact with foliage or sawdust.
That is primarily as a result of tridecyl resorcinol associated to an allergen referred to as Toxicodendron.
The flower buds and fruits produced by the tree are cyanogenic.
You additionally like this Australian tree: Bottle Brush tree (Callistemon)
Propagate Silk Oak
Silk Oaks is propagated with seeds.
Nevertheless, germination is delayed and sometimes uneven regardless of them having no dormancy.
To enhance germination, soak the seeds in chilly water for no less than 24 hours earlier than sowing them.
Afterward, begin them in a greenhouse in particular person containers or shady seedbeds.
The seeds could then take roughly 2 to four weeks to germinate and is transplanted into their everlasting location as soon as they’ve reached Eight” – 12” inches in top.
Or propagate Silk Oak with cuttings.
Use cuttings of half-ripe wooden, about 2” – three” inches with heel and plant them within the June/July body.
Silver Oak Pest or Illness Issues
When planted in poorly drained soils and overwatered, the Silk Oak is inclined to root harm.
The species is understood to be significantly immune to honey fungus and wooden rot.
When planted in lowland circumstances, particularly within the Caribbean, Silk Oak is affected by the dimensions insect often known as Asterolecanium pustulans.
Termites are an issue particularly if planted in dry circumstances in Africa.
Advised Silky Oak Makes use of
Apparently, the Silky Oak flowers are one of many richest sources of nectar.
The nectar is edible and is extracted immediately from the flowers.
Additionally, the nectar falls in showers if you shake the flowers.
The tree additionally yields small quantities of gum resin used for industrial functions.
Mostly, the Silky Oak species have been utilized in agroforestry, particularly for reforestation in Nepal.
It’s not wonderful for colonizing disturbed land but in addition used as a shade tree offering shade to different crops.
Different industrial makes use of of Silk Oak embody the extraction of yellow and inexperienced dyes from the leaves.
It’s incessantly used as a windbreak.
Up to now, earlier than the arrival of aluminum, Silky Oak wooden was used to make exterior window joinery and different furnishings.
Larrivée, a guitar producer, used the wooden to make the facet and backwoods of their devices.
Nevertheless, as a result of declining populations of the species, felling has been discouraged and restricted in a number of areas.