Overview
Summary
Grevillea johnsonii, also known as Johnson's Spider Flower, is an evergreen shrub native to New South Wales, Australia. It's named after Dr. Lawrence Johnson, former director of the Sydney Botanical Garden. This fast-growing shrub thrives in well-drained, slightly acidic soils and full sun, requiring protection from heavy frosts.
Key Features
Grevillea johnsonii typically grows 2-4 metres tall with a 1.5-2.5 metre spread. It's renowned for its vibrant pink to red-orange flowers in terminal clusters during spring, featuring curled, snail-shell-like shapes and long stamens. The shrub boasts delicate, dark green foliage with long, needle-like leaves divided into narrow lobes, 20-25 cm in length.
Natural Habitat
Native to New South Wales, Australia, Grevillea johnsonii thrives in coastal and near-coastal areas. It's adapted to well-drained, sandy or rocky soils and prefers full sun to partial shade. In its natural habitat, this shrub withstands moderate drought and light frost, making it a resilient species in its native range.
Growing Guide
Grevillea johnsonii thrives in specific conditions, requiring careful attention to its growing requirements. Follow these guidelines to successfully cultivate this striking Australian native in your garden.
Requirements
Grevillea johnsonii grows best in full sun and well-drained, acid to neutral soil. It reaches 1.5-2.5 metres in height and spread, maturing in 3-4 years. This shrub tolerates poor, dry soils but avoid chalky or limestone-rich ground. Plant in sheltered, west or south-facing positions for optimal flowering. It's suited to mild temperate climates with light frost tolerance.
Planting Tips
Choose a sunny, sheltered spot with well-draining soil. Prepare the planting area by mixing in organic matter and sand to improve drainage. Dig a hole twice the size of the root ball and place the plant at the same depth as it was in its container. Water thoroughly after planting and mulch around the base to retain moisture.
Maintenance
Prune Grevillea johnsonii lightly after flowering to maintain shape and encourage bushiness. Water deeply but infrequently, allowing the soil to dry between waterings. Apply a slow-release, low-phosphorus fertiliser in spring. Monitor for pests like scale insects and treat if necessary. Protect young plants from severe frost in winter with horticultural fleece.
Uses & Benefits
Grevillea johnsonii offers a range of benefits and uses in gardens and landscapes. This versatile shrub excels in various applications, from ornamental planting to wildlife attraction.
Garden Design
Grevillea johnsonii enhances garden designs with its striking appearance. Plant it as a focal point in sunny borders or use it to create natural screens. Its tolerance for poor, well-drained soils makes it ideal for slopes and dry garden beds. Consider grouping multiple plants for a dramatic effect or use it as a backdrop for smaller perennials.
Wildlife Benefits
This shrub attracts a variety of wildlife to your garden. Its nectar-rich flowers are a magnet for native birds, particularly honeyeaters, as well as bees and butterflies. By incorporating Grevillea johnsonii into your landscape, you're creating a valuable food source for local fauna and supporting biodiversity in your area.
Special Features
Grevillea johnsonii boasts unique characteristics that set it apart. Its spider-like flowers provide year-round interest, while its drought tolerance makes it a low-maintenance choice for water-wise gardens. The plant's ability to thrive in coastal areas and its resistance to light frost further enhance its versatility in various climates.
Problems & Solutions
Growing Grevillea johnsonii can present some challenges, but with proper care and attention, you'll successfully cultivate this beautiful shrub. Here's what you need to know about common issues, care tips, and seasonal considerations.
Common Issues
Grevillea johnsonii can cause skin irritation or allergic reactions when handled. Wear gloves and protective clothing when working with the plant. It's susceptible to honey fungus and leaf spot diseases caused by fungi like Placoasterella baileyi and Seimatosporium grevilleae. The plant's interaction with fires increases its disease susceptibility, making conservation efforts crucial.
Care Tips
Propagate Grevillea johnsonii using semi-hardwood cuttings to mitigate extinction risk. Ensure well-draining, slightly acidic soil and full sun exposure. Prune lightly after flowering to maintain shape and encourage new growth. Water deeply but infrequently, and apply a low-phosphorus, slow-release fertiliser in spring. Monitor for pests and diseases regularly, addressing issues promptly.
Seasonal Notes
In spring, Grevillea johnsonii produces vibrant pink to red-orange flowers, attracting native birds and insects. Protect young plants from severe frost during winter. The shrub can regenerate after fire from epicormic buds on trunks and branches, and from a basal lignotuber. In summer, maintain consistent watering during dry spells. Autumn is ideal for light pruning and preparing the plant for winter.
Additional Information
Grevillea johnsonii offers more than just its striking appearance and wildlife-friendly attributes. Here's some additional information to enhance your understanding of this remarkable Australian native shrub.
Varieties
Grevillea johnsonii doesn't have many cultivated varieties. The species itself is prized for its natural form and vibrant flowers. Gardeners typically grow the standard species, which showcases the characteristic pink to red-orange flowers and needle-like foliage. Its consistent appearance makes it a reliable choice for landscaping projects.
Where to Buy
You can purchase Grevillea johnsonii from specialised Australian native plant nurseries. These nurseries often stock a range of sizes, from small seedlings to more mature plants. Online plant retailers also offer this species, providing convenient shipping options. Local botanical gardens may sell this plant during their seasonal plant sales.
Resources
For more information on Grevillea johnsonii, consult the Australian Native Plants Society website. The Royal Botanic Gardens Sydney offers comprehensive guides on native plant cultivation. Academic journals, such as the Australian Journal of Botany, provide in-depth studies on Grevillea species. Local horticultural societies often organise workshops and talks on native plant care.