Grevillea Trees: The Overlooked Beauty of Tree-Form Grevilleas

Overview

When most gardeners think of grevilleas, they picture colourful flowering shrubs filling a garden bed, or ground covers cascading over retaining walls and spilling across sunny banks. Rarely do they imagine them as trees.

Yet some of the most spectacular grevilleas are those grown in tree form. Rising above the surrounding landscape, the light-filled canopy features intricate foliage that filters sunlight, creating gentle movement in the breeze, adding depth and character to the garden.

Their extraordinary flowers, with unique shapes and delicate forms, appear in abundance, creating bursts of colour throughout the landscape. Rich in nectar, they attract honeyeaters, lorikeets, native bees and other pollinators, transforming the tree into a vibrant living feature.

Grevillea trees: beyond shrubs and ground covers

Grevilleas have long been popular in Australian gardens for their versatility, adaptability, distinctive beauty and ease of care across a wide range of landscapes. Low-growing grevilleas are valued as reliable ground covers, while shrubby forms are often used as feature plants and informal screens.

Despite their popularity in low-growing and bushy forms, the potential of grevilleas as trees is often overlooked. When grown into tree form, grevilleas retain the qualities that make the genus unique while revealing a different expression of their beauty within the landscape.

Their finely textured foliage, sculptural branching, uniquely formed nectar-rich flowers and ability to attract native wildlife create a living feature that evolves throughout the year.

Grevillea trees with dense spiny or prickly leaves, such as Grevillea tenuiloba standard, provide valuable refuge for small native birds by offering additional protection from predators like domestic cats.

Together, grevillea trees bring the unique character into the canopy layer of your garden, combining beauty, biodiversity and a distinctly Australian presence.

Grevillea trees: from majestic canopies to weeping standards

Grevilleas offer an extraordinary range of forms for landscape design, from naturally large, stately trees with strong architectural appeal to compact shrubs that can be shaped into small, elegant feature trees.

Many shrubby grevilleas can be trained or grafted to become ‘standard’ forms, revealing their foliage and flowers above a clear trunk. Certain species and cultivars develop a graceful weeping profile with cascading branches, bringing softness and movement to the garden.

Before selecting the right grevillea tree for your garden, consider your local climate, soil type, available space and the tree’s mature size to ensure it will thrive for years to come.

Naturally tree-form grevilleas

Grevillea robusta (Silky Oak)

Silky Oak (Grevillea robusta) is the largest member of the Grevillea genus, distinguished by its strong central trunk and stately tree form. It is fast-growing and generally reaches 10 – 15 m in residential gardens.

Young trees display a stunning, neat conical or pyramidal canopy before evolving into a broad, spreading crown that lends grandeur, shade and architectural presence to the landscape.

This grevillea tree is renowned for its finely divided, fern-like foliage, with dark green upper surfaces and distinctive silvery undersides that shimmer in the breeze.

From spring to early summer, the canopy is covered with striking golden-orange flower spikes up to 12 cm long, creating a brilliant display against the finely textured foliage.

While Silky Oak is classified as an evergreen species, it can exhibit semi-deciduous behaviour in cooler climates where heavy winter frosts often cause partial leaf drop.

Grevillea baileyana (White Oak, Brown Silky Oak)

Similar to Silky Oak, White Oak (Grevillea baileyana) grows to a similar height but at a somewhat slower rate. In smaller suburban gardens with cooler climates, it often stays well under 10 m.

This grevillea tree typically develops a strong, upright central trunk, although it occasionally forms multiple stems. This natural variation gives rise to a range of canopy shapes, from slender columnar to broad, rounded or dome-shaped crowns.

One of the tree’s most distinctive features is its two-tone foliage, where glossy, deep green upper surfaces contrast with brilliant bronze-gold undersides, creating a shimmering effect as the elliptical leaves (up to 20 cm) move in the wind.

Masses of cylindrical flower spikes emerge in late spring and summer, producing copious sticky nectar that attracts honeyeaters, lorikeets, and other native birds.

Grevillea barklyana (Gully Grevillea)

Grevillea barklyana is a graceful small tree that showcases a different side of the grevillea genus. Unlike many popular grevilleas grown primarily for their flowers, this species is valued for its elegant structure, distinctive foliage and refined woodland character.

This grevillea tree tends to develop an upright trunk with an open, spreading canopy, making it an excellent choice where a smaller native tree with a light, airy presence is desired.

One of its most striking features is its large, deeply divided foliage, with narrow lobes that create a soft, fern-like texture. The finely cut leaves give the canopy a delicate appearance. During the flowering season, Grevillea barklyana produces clusters of pink to reddish flowers, providing seasonal colour.

Its combination of fine foliage, sculptural branching and elegant form makes it one of the most refined tree-form grevilleas available.

Shrubby grevilleas trained into small trees

Many popular grevilleas naturally grow as large shrubs, but with careful pruning and training they can be developed into elegant small trees with a clear trunk and elevated canopy.

This approach allows gardeners to enjoy the outstanding flowers, fine foliage and wildlife appeal of shrub-form grevilleas while introducing height, structure and vertical interest into the landscape.

Unlike naturally tree-forming species, these grevilleas require early shaping to establish a strong framework. Lower branches are gradually removed to encourage a single trunk or a selected multi-stemmed form, allowing the canopy to develop above ground level.

Once established, they create a softer, more ornamental tree silhouette while retaining the dense flowering character that makes these grevilleas so popular.

Popular varieties

• Grevillea ‘Moonlight’: A classic choice for a small tree, ‘Moonlight’ develops an elegant upright form with fine foliage and exceptionally large cream-white flower clusters. When trained with a clear trunk, it creates a graceful feature tree with a light, airy canopy.
• Grevillea ‘Honey Gem’: One of the most popular large grevilleas, ‘Honey Gem’ can be trained into a small tree with an upright habit and dense foliage. Its golden-orange flower spikes are highly attractive to honeyeaters and other nectar-feeding birds.
• Grevillea ‘Sandra Gordon’: A superb landscape plant known for its large golden-yellow flower clusters and refined foliage. It naturally develops into a large shrub or small tree, making it one of the easiest grevilleas to establish as a tree-form specimen.
• Grevillea ‘Robyn Gordon’: A highly adaptable and widely grown cultivar with vibrant red flowers and fine foliage. Although often maintained as a shrub, older plants can be trained into small multi-stemmed trees with a relaxed, natural character.
• Grevillea ‘Misty Pink’: A softer, more delicate selection featuring pink flowers and attractive foliage. Its graceful growth habit makes it suitable for smaller gardens where a refined flowering tree is desired.
• Grevillea ‘Ivanhoe’: A vigorous cultivar with dense foliage and striking flowers, valued for its ability to create a fuller canopy. When trained as a tree, it provides strong structure while retaining the dense, textured character typical of many grevilleas.
• Grevillea ‘Superb’: A reliable and colourful cultivar featuring vivid flowers and attractive foliage. As a small tree, it develops a compact yet striking form, combining the beauty of a flowering canopy with its sculptural presence.

Training tips

Training a shrubby grevillea into a small tree requires patience and early intervention. The best results are achieved by selecting a young plant with a strong central stem or a few well-positioned stems and gradually developing the desired structure over time.

• Select the right framework: Choose a healthy stem to become the main trunk, or retain several evenly spaced stems if a multi-trunk form is preferred. Remove competing lower shoots to encourage an elevated canopy.
• Prune gradually: Avoid removing too much growth at once. Slowly raise the canopy by removing lower branches in stages, allowing the trunk to strengthen while maintaining enough foliage for healthy growth.
• Encourage balanced branching: Once the desired trunk height is reached, allow upper branches to develop into a rounded, natural canopy. Light pruning can help maintain a balanced shape while preserving the plant’s flowering habit.
• Start early: Large established shrubs can be difficult to convert into attractive trees. Training young plants from the beginning gives the best chance of developing a strong trunk and well-proportioned canopy.

Weeping standard grevilleas

Weeping standards are typically created by grafting naturally cascading or prostrate Grevillea species, cultivars or hybrids onto the trunk of a vigorous rootstock (often derived from Grevillea robusta). The result is a spectacular miniature ornamental tree, with a clear trunk supporting a gracefully cascading canopy of foliage and flowers.

Because these forms require specialised propagation, careful training and time to develop, established weeping standards are often significantly more expensive than shrub-form grevilleas in the nursery. Nonetheless, they come with many benefits.

Ideal for very small gardens

These grevillea trees are particularly well suited to compact spaces. Once the desired trunk height has been established, they gain most of their growth by developing a broader, denser cascading canopy rather than becoming significantly taller.

Compact root systems

Because weeping standard grevilleas are grown as small ornamental trees, they typically develop a compact canopy supported by a relatively modest root system compared with larger ornamental trees.

Instant feature plant

With their elevated, cascading canopy and graceful silhouette, these grevillea trees instantly become living sculptures in the landscape. They are ideally suited to courtyards, patios, balconies, tight garden beds and sunny formal entrances, where their distinctive form provides year-round visual interest.

Popular varieties

• Grevillea ‘Poorinda Royal Mantle’ (standard): The most common weeping grevillea standard features a dense cascading habit and bright red tooth flowers, highly prized for its full ‘waterfall’ effect.
• Grevillea ‘Royal Mantle’ (standard): This grevillea tree is more vigorous with long trailing branches. It features larger red flowers.
• Grevillea ‘Bronze Rambler’ (standard): The classic weeping standard showcases bronze new growth, providing excellent foliage contrast. Its finer texture makes the cascading branches even more graceful.
• Grevillea x Gaudichaudii (standard): A less common but striking variety that features lobed, oak-like foliage with a soft blush of pink and bronze in new growth and deep burgundy-red flowers.

Maintenance tips

• Staking: The elevated canopy and graft union may create a top-heavy structure supported by slender trunks. Keep a young tree securely tied to a sturdy timber or metal stake to prevent the trunk from bending or snapping, especially in windy locations.
• Removing suckers: Remove any shoots that emerge from below the graft union as soon as they appear. These suckers grow from the rootstock and can divert energy away from the grafted canopy, reducing its vigour and altering the plant’s appearance.
• Pruning: To maintain the graceful cascading ‘waterfall’ effect, lightly trim the lower branches to keep them clear of the ground. After flowering, selectively thin and shape the upper canopy to encourage fresh, dense growth while preserving the plant’s natural weeping habit.

Final words

Grevilleas are often planted for what occurs close to the ground: colourful flowers, spreading foliage and their ability to fill difficult spaces. But when allowed to rise into tree form, they reveal a different side of the genus.

A grevillea tree is not simply an alternative to other ornamental trees. Its value comes from the combination of a distinctive canopy, unusual foliage textures, nectar-rich flowers and the wildlife it brings into the garden.

From towering species such as Silky Oak to refined small trees and cascading standards, grevilleas offer an impressive range of forms. Growing them as trees introduces structure, character and ecological value through a plant with a distinctly Australian identity.

FAQs

How tall do grevillea trees grow?

The height of grevillea trees varies greatly depending on the species, cultivar and growing conditions.

Large tree-form species such as Silky Oak (Grevillea robusta) can reach 20 metres or more in favourable environments, while many landscape grevilleas grown as small trees typically reach around 4 – 10 metres.

Standard and weeping forms are usually much smaller, with their final height largely determined by the rootstock trunk and the canopy selection above it.

What is the best grevillea tree variety for Australia?

There is no single best grevillea tree for every Australian garden, as the ideal choice depends on climate, available space and the desired landscape style.

For a large feature tree, Grevillea robusta (Silky Oak) is one of the most impressive choices, providing height, structure and a spectacular flowering display.

For smaller gardens, tree-form cultivars such as Grevillea ‘Moonlight’, Grevillea ‘Honey Gem’, and Grevillea ‘Sandra Gordon’ are excellent choices, combining elegant form with abundant flowers and wildlife appeal.

For a more sculptural feature in a tight space, weeping standards offer a unique cascading form that suits smaller courtyards and compact landscapes.

Do grevillea trees have invasive roots?

Grevillea trees generally do not develop aggressive, surface-disrupting root systems, often seen associated with some large exotic trees. Most landscape grevilleas develop relatively manageable root systems that suit residential gardens, particularly smaller tree-form cultivars and standard forms.

However, root behaviour depends on the species, tree size, soil conditions and available moisture.

Large species such as Silky Oak (Grevillea robusta) can develop a more extensive root system as they mature, so they should be planted with adequate space from buildings, paving and underground services.

Smaller grevillea trees and standard forms are usually better choices for compact gardens where root space is limited.

How long do grevillea trees live?

The lifespan of grevillea trees varies widely depending on the species, growing conditions and care. Many smaller grevilleas grown as landscape trees typically live for 20 – 50 years, while larger, naturally tree-forming species can survive considerably longer under favourable conditions.

Factors such as soil drainage, climate, watering practices and pruning can greatly influence longevity. Selecting the right species for the site is one of the most important factors in ensuring a healthy, long-lived grevillea tree.