| Botanic name | Banksia marginata |
| Other names | Silver banksia, honeysuckle |
| Main Origin | Southeastern Australia |
| Mature size | 1 – 5 m x 2 – 10 m (w x h) |
| Mature form | Shrub or small tree |
| Foliage | Narrow, oblong, dark green with silvery grey underside |
| Growth rate | Moderate to fast |
| Position | Full sun, light shade |
| Soil | Adapts to most soils |
| Water | Occasional deep watering during extended dry periods |
| Climate | Mediterranean, temperate, mild subtropical |
| Flower | Yellow cylindrical spikes mainly in autumn and winter |
| Use | Feature specimen, screening, shade tree |
| Notes | Suitable for coastal sites, cold-tolerant |
IN THIS ARTICLE
Overview
Banksia marginata, commonly known as Silver Banksia, is one of the most adaptable and visually appealing Banksia species.
The plant shows remarkable variation in form, ranging from a low, compact shrub to a tall, upright tree reaching up to 10 metres. Its attractive habit, deep-green foliage, and striking soft yellow flower spikes give it year-round ornamental value.
Hardy, fast-growing, and long-lived, Banksia marginata thrives in a wide range of conditions, making it a reliable and attractive choice for home gardens and public spaces.
Origin and distribution
Banksia marginata, commonly known as Silver Banksia, is indigenous to a broad region of southeastern Australia. The hardy and adaptable species can be found in diverse habitats, including coastal heaths, dry forests, woodlands, shrublands, floodplains, and even swamps.
From coastal dunes to subalpine slopes, its wide distribution has led to significant genetic diversity, resulting in variations in form, foliage size and shape, and growth conditions. Successful establishment of the plant often requires sourcing plants from the appropriate provenance.
The plant is widely valued in Australian cultivation, recognised as a reliable choice for gardens, parks, and revegetation projects across diverse environments and climates. It is the only Banksia species naturally found in Canberra.
Growth and care
Banksia marginata thrives in a range of climates, from cold subalpine or cool temperate to warm temperate and mild subtropical. The wide adaptability to different climate zones is a key factor in its popularity and success in cultivation across diverse Australian regions.
In mountainous and higher altitude regions, established plants can withstand cold winters with heavy frosts and even snow, making them highly cold-tolerant (down to -10°C). The plant naturally prefers low to moderate humidity during warmer seasons.
Banksia marginata is known for its ability to grow in a wide range of soil types, whether light or heavy, wet or dry, depending on the plant’s provenance. Distinct from many other banksias, such as Banksia menziesii, some forms of Banksia marginata can sustain moist or waterlogged sites, although good drainage is generally preferred for optimal growth.
Overall, the plant is drought-resistant once established. It also tolerates a wide pH range of soils, as evidenced by its growth in highly acidic soils in the Grampians in Victoria and alkaline soils in South Australia.
Like all banksias, Banksia marginata develops proteoid roots, which help it thrive in nutrient-poor soils. It is adapted to low-phosphorus environments and can be negatively impacted by high phosphorus levels. Additional fertilisation is often unnecessary.
The plant requires minimal pruning. Removing dead or damaged branches and spent flower spikes is often sufficient to maintain its natural form. If a specific shape is desired, prune after flowering and avoid pruning into leafless stems.
Some forms of Banksia marginata have lignotuber (a woody swelling at the base of the stem for regeneration after fire or other damage), while others don’t. The plant can respond to hard pruning if a lignotuber is present.
Features
Banksia marginata is highly variable and adaptable, exhibiting a range of distinctive features that contribute to its widespread appeal and success in diverse Australian landscapes.
The hallmark is its variable form, depending on its specific provenance and growing conditions. While it often appears as a medium shrub at a height of around 2 – 3 metres, it can also be found as a scrambling, prostrate plant in some environments. Alternatively, the species can develop into a small to medium-sized tree, reaching a height of 10 – 12 metres.
Its bark is usually greyish-brown, relatively smooth on younger stems, becoming rougher, fissured, and sometimes tessellated (cracked into squares) on older trunks and branches.
The variability extends to its foliage. While typically linear to oblong, leaves vary in length and width across different populations. Some forms show recurved leaf margins (hence ‘marginata’), while others display smooth or serrated margins.
The upper surface of its foliage is dark, glossy green, while the underside is distinctly white or silvery due to a dense covering of fine hairs, giving the plant its common name.
Banksia marginata produces striking pale to bright yellow cylindrical flower spikes, typically between 5 and 15 cm long and 4 – 6 cm wide. Flowering time can vary significantly based on the growing location. Most areas experience blooms from late summer to early winter. After flowering, the spikes mature into prominent, woody seed cones.
With unparalleled versatility and adaptability, Banksia marginata holds immense value in landscaping. Coupled with its attractive silvery-backed foliage and brilliant yellow flower spikes that provide vital nectar for native wildlife, Banksia marginata offers a low-maintenance, aesthetically pleasing, and ecologically beneficial solution for creating robust and beautiful landscapes.
Dwarf forms
- Minimarg (syn. Mini Marg): This is the most common dwarf variety selected from the northeast coast of Tasmania. It grows as a compact, dense, rounded shrub with 0.5 – 1.5 metres in height and width, excellent for low hedges, rockeries, or smaller garden spaces.
- Coastal Spread: As its name suggests, this variety has a low-growing, spreading form. It often develops into a dense, mounding groundcover or small shrub, reaching around 1 – 2 metres in height and 2 – 3 metres in width, well-suited for covering embankments and large garden beds.
- Mallacoota Dwarf: This is another popular dwarf selection, originating from a natural population at Mallacoota, Victoria. It has a compact habit and small size similar to ‘Minimarg’.
