Grevillea Obtusifolia

Gin Gin Gem

Botanical Name: Grevillea obtusifolia
Family: Proteaceae
Origin: South-western Western Australia (coastal limestone plains & dunes)
Plant Type: Evergreen prostrate shrub (groundcover, spreading)

Overview

A tough, mat-forming grevillea ideal for Adelaide/South Australian gardens. It knits into a dense, weed-suppressing carpet of grey-green foliage and carries pink-to-red and cream “spider” flowers mainly late autumn–spring, with spot blooms outside peak. Loves full sun, heat and coastal conditions, and is particularly good on the neutral–alkaline (calcareous) soils common on the Adelaide Plains—just keep drainage decent and fertiliser low in phosphorus.

Key Features

• Mature Size: 0.2–0.4 m H × 1.5–3 m W (can trail further over walls)
• Growth Rate: 20-50 (spread) cm per year under good conditions
• Foliage: Small obovate/rounded grey- to blue-green leaves; soft bronze tints on new growth
• Flowers: Clusters of pink-red & cream spider blooms, mainly late autumn–spring
  
• Seasonal Interest: Winter–spring colour; silver-green carpet year-round
• Wildlife Value: Nectar magnet for honeyeaters & native bees; low, dense cover for small fauna
• Tolerance: Drought-tolerant once established; heat & wind hardy; front-line to second-line coastal tolerant; light–moderate frost; handles poor/rocky or sandy soils; avoid waterlogging & high-P fertilisers
• Planting Density: Mass cover 1 plant per 1–1.5 m² (≈ 1.0–1.2 m centres); edge/spill-over 0.8–1.0 m apart
• Pet Friendly: Generally non-toxic; foliage/sap may irritate sensitive skin—wear gloves when pruning

Where It Works Best

• Sunlight: Full sun to light part shade (best flower in sun)
• Soil: Free-draining sands or sandy/loam; thrives on neutral–alkaline (calcareous) Adelaide soils; on heavier clays raise/mound to keep crowns dry in winter
• Water Needs: Establishment: 2 deep soaks/week for 8–12 weeks. Established: deep soak every 3–4 weeks in summer (weekly in heatwaves); minimal in winter
• Maintenance: Tip-prune lightly after flowering to keep dense (avoid cutting into bare old wood). Mulch annually; feed in spring with a low-phosphorus native fertiliser only; add organic matter/occasional iron chelate if foliage pales on very alkaline sites
• Lifespan: 10–20+ years in well-drained positions
• Climate Zones: Temperate & Mediterranean SA—excellent on Adelaide Plains and coastal suburbs; choose free-draining, frost-sheltered microclimates in the Hills
• Soil pH: Neutral to slightly alkaline (tolerates slightly acidic if well-drained)

Landscape & Design Ideas

• Coastal banks, verges & embankments (binds soil, shrugs off salt & heat)
• Rockeries/retaining walls and path edges—great spill-over
• Low, water-wise native mixes with lomandra, dianella & westringia
• Under open eucalypts where light is dappled and soils are lean

Why You Will Love It

A beautiful, bird-attracting groundcover that thrives on Adelaide sun, salt and lean soils, delivering months of colour and a neat, weed-suppressing mat with minimal fuss.