Overview
Summary
Grevillea banksii, commonly known as Banks' grevillea or dwarf silky oak, is a flowering plant native to Queensland, Australia. It's a versatile species that can grow as a shrub or small tree, reaching heights of 2-10 metres. The plant is prized for its attractive flowers and adaptability to various growing conditions.
Key Features
Grevillea banksii boasts distinctive bottlebrush-like flowers in red or white. Its leaves are deeply lobed and silvery-green, providing year-round interest. The plant's form varies from erect and bushy to prostrate, making it suitable for different landscape applications. It's also known for its hardiness and ability to thrive in poor soils.
Natural Habitat
In its native Queensland, Grevillea banksii thrives in coastal and sub-coastal areas. It's often found in sandy or rocky soils, tolerating both well-drained and seasonally waterlogged conditions. The plant has adapted to withstand periods of drought and can grow in full sun to partial shade, making it a resilient species in its natural environment.
Growing Guide
Cultivating Grevillea banksii is straightforward with the right conditions. This guide covers essential requirements, planting tips, and maintenance for successful growth.
Requirements
Grevillea banksii thrives in full sun to partial shade and well-draining soil. It's hardy in zones 9-11, tolerating temperatures down to 24°F (-4°C). The plant prefers neutral to acidic soil and is sensitive to high phosphorus levels. Ensure good air circulation and avoid waterlogged conditions. Grevillea banksii adapts well to various soil types, including sandy or rocky soils.
Planting Tips
Plant Grevillea banksii in spring or autumn for optimal establishment. Choose a location with adequate space for growth, considering its mature size. Prepare the soil by improving drainage if necessary and adding low-phosphorus fertiliser. Dig a hole twice the size of the root ball, place the plant, and backfill with soil. Water thoroughly after planting to settle the roots.
Maintenance
Prune Grevillea banksii regularly to maintain shape and encourage bushiness. Remove dead or damaged branches as needed. Water deeply but infrequently, allowing the soil to dry between waterings. Apply a low-phosphorus, slow-release fertiliser annually in spring. Mulch around the base to retain moisture and suppress weeds, keeping mulch away from the stem. Monitor for pests like scale insects and treat promptly if detected.
Uses & Benefits
Grevillea banksii, also known as Banks' grevillea or dwarf silky oak, offers numerous benefits and versatile uses in gardens and landscapes. This Australian native plant is prized for its colourful flowers, variable growth habit, and adaptability to various garden styles.
Garden Design
Grevillea banksii adapts well to different garden styles, from traditional cottage gardens to modern landscapes. It's ideal for screening, specimen planting, and coastal gardens due to its tolerance for exposed positions and salt spray. You can grow it in well-draining soils with pH 5.5-7.0, making it suitable for acidic to neutral soil conditions.
Wildlife Benefits
This plant attracts a variety of pollinators, including birds and insects, to your garden. Its nectar-rich flowers provide a valuable food source for native wildlife, especially honeyeaters and other nectar-feeding birds. By incorporating Grevillea banksii into your garden, you'll create a thriving ecosystem that supports local biodiversity.
Special Features
Grevillea banksii's versatility extends to its use in tubs, planter boxes, and as ground covers or spill-overs. It's also a parent of several popular hybrids, such as G. 'Robyn Gordon', G. 'Superb', and G. 'Misty Pink'. These cultivars offer a range of flower colours and growth habits, allowing you to choose the perfect variety for your specific garden needs.
Problems & Solutions
Grevillea banksii, while generally hardy, can face several challenges in cultivation. Here's a guide to common issues, care tips, and seasonal considerations to help you maintain a healthy plant.
Common Issues
Grevillea banksii is susceptible to root rot in poorly drained soils. It's frost-tender, requiring protection in colder climates. The plant can cause contact dermatitis due to alkyl resorcinols, and its flowers and seed pods contain toxic hydrogen cyanide. In non-native areas, it may become invasive, outcompeting local vegetation.
Care Tips
Plant Grevillea banksii in well-drained, sandy to gravelly clay soils with a pH of 5.5-7.0. Ensure full sun to partial shade exposure. Prune regularly to maintain shape and promote air circulation. Water deeply but infrequently, and apply a low-phosphorus fertiliser annually. Monitor for scale insects and other pests regularly.
Seasonal Notes
In spring, apply mulch to retain moisture and suppress weeds. Summer calls for increased watering during dry spells. Autumn is ideal for planting or transplanting. In winter, protect from frost if temperatures drop below 5°C (41°F). Prune after flowering to encourage bushiness and maintain the desired shape throughout the year.
Additional Information
Grevillea banksii offers diverse varieties and is readily available through various nurseries. Here's some additional information to help you explore this fascinating plant further.
Varieties
Grevillea banksii comes in two main forms: the tree form and the 'Forsteri' variety. The tree form grows up to 10 metres tall with spreading branches, producing lobed leaves and cream to red flowers. 'Forsteri' is an upright, bushy shrub reaching 3 metres, featuring silvery leaves and red or white flowers in spring.
Where to Buy
You can purchase Grevillea banksii from specialist native plant nurseries, garden centres, and online retailers. Look for reputable suppliers who offer healthy, well-established plants. Some nurseries may offer both the tree form and 'Forsteri' variety, allowing you to choose the best option for your garden.
Resources
For more information on Grevillea banksii, consult Australian native plant societies, botanical gardens, and horticultural websites. These resources often provide detailed cultivation guides, identification tips, and landscaping ideas. Local gardening clubs and native plant enthusiasts can also offer valuable insights and practical advice on growing this species.