Silky oak (Grevillea robusta)

Also known as: Silver oak, Southern silky oak

The southern silky oak, known for its abundant and eye-catching blossoms, makes an excellent choice for parks. The tree's dense canopy offers substantial shade, creating a pleasant environment for park-goers. Its vibrant flowers attract a variety of wildlife, including bees, butterflies, and birds, enhancing the park's ecosystem. Additionally, the durable, rot-resistant wood of the southern silky oak was historically valued for outdoor window joinery before aluminum became widespread.

In This Article

Care Tips Water Sunlight Temperature Soil Fertilize Prune Propagation Repotting Toxicity

Attributes of Silky oak

Lifespan

Perennial

Plant Type

Tree

Plant Height

5 m to 40 m

Spread

8 m to 9 m

Leaf Color

Green

Flower Size

8 cm to 15 cm

Flower Color

Yellow Orange Gold

Images of Silky oak

Quickly Identify Silky oak

Grevillea robusta can be recognized by its deeply dissected, pinnate leaves which appear fern-like. The leaves are dark green above and silver-grey beneath. The flowers are bright yellow-orange and appear in dense, cylindrical clusters.

Scientific Classification of Silky oak

Phylum

Vascular plants

Class

Dicotyledons

Order

Proteas, lotuses, planes, and allies

Family

Protea

Genus

Spider Flowers

Species

Silky oak

Planting and Growing of Silky oak

Care Difficulty

Easy

Watering Schedule

Every 4 days

Sunlight Requirements

Full sun

Sunshine Duration

6-8 hours

Ideal Temperature

60-77℉

Soil Type

Potting Mix, Peat Mix

Soil pH

6.5-7.5

Fertilizer Type

Balanced

Pruning Season

Spring, Summer

Pruning Area

Branches, Leaves

Pruning Frequency

2 times a year

Repotting Season

Spring

Pot Type

Plastic, Ceramic

How to Water Silky oak?

When watering Grevillea robusta, aim for a generous soaking that allows the water to penetrate deep into the root zone, ideally about 500ml. Ensure that the soil is consistently moist but not soggy. Allow the top inch of soil to dry out between waterings to avoid over-watering.

What are the symptoms of an underwatered Silky oak? ›

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What are the symptoms of an overwatered Silky oak? ›

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What Are the Sunlight Requirements for Silky oak?

Sunlight Requirements: Full sun, Partial sun

Duration of light: 6 to 8 hours

The ideal light range for Grevillea robusta involves exposure to full sun conditions, allowing unfiltered sunlight to aid photosynthesis. This promotes vigorous growth, enhances foliage health, and supports flowering cycles efficiently.

What is the best lighting condition for Grevillea robusta? ›

What solutions exist to achieve ideal light exposure for the plant? ›

What benefits does the plant receive from ideal lighting? ›

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What Is the Ideal Temperature Range for Silky oak?

Ideal Temperature: 60 ~ 77℉

The ideal temperature range for Grevillea robusta, commonly known as the Silk Oak, is between 60°F and 77°F. Within this range, the plant will grow optimally and exhibit healthy foliage and growth patterns. The temperatures mimic its native environment, ensuring balanced moisture and nutrient uptake for vibrant development.

What Soil is Best for Silky oak?

Soil type: Sandy soil, Loam, Clay soil

Soil PH: 6.5 ~ 7.5

Grevillea robusta thrives in well-draining soils that prevent water from pooling around the roots. Proper drainage reduces the risk of root rot and supports healthy root development, essential for the tree’s growth and stability. This plant prefers soils enriched with organic matter, offering essential nutrients that enhance growth and flowering. Nutrient-rich soil ensures robust foliage and a resilient structure, enabling the plant to withstand various environmental stressors. Grevillea robusta benefits from soil with moderate moisture retention, which maintains a consistent level of hydration while minimizing the risk of overwatering. This balance helps sustain the tree’s health and promotes lush, vigorous growth. More About Soil→

How to Fertilize Silky oak?

Fertilizer type: Balanced

Grevillea robusta thrives with a balanced approach to fertilization. It's generally recommended to use a diluted liquid fertilizer, applying approximately half the strength advised on the package once every two weeks during the growing season. Be cautious not to over-saturate the soil, ensuring proper drainage to mimic its native habitat. More About Fertilizing Techniques→

How to Prune Silky oak?

Pruning Time: Spring, Summer

Start pruning by sanitizing your tools to prevent disease spread. Focus on removing dead or diseased branches first. Trim back any excessively long branches to maintain the shape of the Grevillea robusta. When cutting, make clean cuts at a slight angle just above a node or leaf bud. This encourages regrowth and helps the plant keep its natural shape. Aim to open the canopy slightly to allow sunlight and air to penetrate the inner branches. More About Pruning Techniques→

How to Propagate Silky oak plant?

Propagate Time: Spring,Early spring,Early summer

Collect seeds from a mature Grevillea robusta pod. Soak them in warm water for 24 hours to break dormancy and enhance germination rates.

Plant the soaked seeds in a seed tray filled with a well-draining seed-starting mix. Cover lightly with soil and maintain moisture through gentle misting.

Select a healthy branch and cut a 10-15cm piece just below a node. Remove lower leaves to prevent rot and dip the cut end in rooting hormone before planting.

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How to Repot Silky oak plant?

Repotting frequency: Every 1-2 years

Grevillea robusta should be repotted when roots begin to emerge from the drainage holes or when growth significantly slows down. This indicates that the plant needs more space to extend its roots and access nutrients. Additionally, if the soil appears depleted, it could reflect a need for repotting to provide fresh, nutritious substrate.

Opt for a pot that is slightly larger than the current one, ensuring it has sufficient drainage holes. Grevillea robusta appreciates an airy environment around the root zone to prevent water stagnation and promote healthy root growth; hence, a terracotta pot can be ideal due to its breathability.

Select a well-draining sandy mix to replicate the natural conditions of Grevillea robusta's native habitat. This type of soil prevents waterlogging, which can lead to root rot, while also providing the plant with the proper texture to establish strong root networks.

Toxicity of Silky oak

Is Silky oak toxic to humans?

Interaction with the silky oak can trigger a toxic response in individuals. This reaction may be serious, necessitating immediate medical intervention. Contact with the sap, bark, flowers, or foliage, or merely being near these components, can lead to eye and skin irritation. The eyes may become inflamed, while the skin may exhibit symptoms such as dermatitis, blistering, and intense itching. Given that these ornamental plants can be cultivated in home gardens or kept as indoor plants, they may be easily accessible to children, who could suffer adverse effects from the toxic elements of this species.

WARNING

The judgment on toxicity and danger is for reference only. We DO NOT GUARANTEE any accuracy of such judgment. Therefore, you SHALL NOT rely on such judgment. It is IMPORTANT TO SEEK PROFESSIONAL ADVICE in advance when necessary.

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