Ficinia Nodosa 'Knobby Club Rush'

Knobby Club Rush / Sea Rush

Botanical Name: Ficinia nodosa (syn. Isolepis nodosa)
Family: Cyperaceae
Origin: Coastal Australia & New Zealand (dunes, swales, estuaries)
Plant Type: Evergreen clumping sedge (grass & strappy)

Overview

A super-tough coastal sedge for Adelaide/South Australia, forming tidy clumps of upright, rush-like stems topped with “knobby” tawny seedheads. Thrives in full sun, wind and salt, and copes with seasonal wet or dry—perfect for verges, swales/rain-gardens, foredunes and modern, low-water landscapes.

Key Features

• Mature Size: 0.6–1.2 m H × 0.6–1.0 m W (clumping)
• Growth Rate: 15-30 cm per year under good conditions
• Foliage: Fine, cylindrical olive- to bright-green stems in dense tussocks; graceful movement in wind
• Flowers: Tawny-brown “knobs” (spikelets) at stem tips, mainly spring–autumn, often present year-round
  
• Seasonal Interest: Year-round vertical texture; warm tawny seedheads through the hot months
• Wildlife Value: Shelter for small birds, lizards & beneficial insects; stabilises banks/dunes
• Tolerance: Drought-tolerant once established, front-line coastal & salt-spray tolerant, heat & wind hardy; takes periodic inundation (swales); light–moderate frost; clay-tolerant if mounded and not waterlogged long-term
• Planting Density: Mass/drifts: 3–5 plants/m² (≈45–60 cm centres). Edging/rows: 3 per metre (≈30–40 cm). Specimen: 0.8–1.0 m from neighbours
• Pet Friendly: Non-toxic to cats & dogs (stems can be scratchy—site away from narrow paths)

Where It Works Best

• Sunlight: Full sun to light part shade (best form in sun)
• Soil: Sands to loams to clay loams; tolerates saline and neutral–alkaline soils common on the Adelaide Plains; raise/mound on heavy clay 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. Tolerates occasional flooding in swales
• Maintenance: Very low—comb or clip out old/tatty stems in late winter; hard cut-back to 10–15 cm every 2–3 years to refresh if needed; fertiliser rarely required
• Lifespan: 10–20+ years in suitable sites
• Climate Zones: Temperate & Mediterranean SA—excellent on Adelaide Plains, Gulf/coastal suburbs and second-line/front-line coastal; choose a frost-sheltered position in colder Hills sites
• Soil pH: Neutral to alkaline (tolerates slightly acidic; also tolerates saline soils)

Landscape & Design Ideas

• Coastal foredunes, embankments & verges (wind and salt hardy)
• Swales/rain-gardens and storm-water basins (handles wet/dry cycles)
• Modern matrix plantings with Lomandra, Dianella, Westringia & grasses
• Poolside/wind-filter accents and low-maintenance containers

Why You Will Love It

The ultimate set-and-forget coastal sedge for Adelaide—salt, wind, heat and drought tough, with elegant movement and year-round structure for minimal water and care.