Dietes Grandiflora

Large Wild Iris / Fairy Iris / Wild Iris / African Iris

Botanical Name: Dietes grandiflora
Family: Iridaceae
Origin: South Africa
Plant Type: Strappy grass-like evergreen perennial

Overview

A tough, repeat-flowering hero for South Australian gardens. Dietes grandiflora forms tidy fans of upright, sword-like green leaves and sends up large white “butterfly” flowers with gold and violet markings from spring through the warm months (often after rain). Perfect for borders, verges, mass plantings and big pots in coastal and Mediterranean climates.

Key Features

• Mature Size: 0.8–1.2 m H × 0.6–1.0 m W (clump)
• Growth Rate: 20-40 cm per year under good conditions
• Foliage: Dense clumps of strappy, mid-green leaves; neat, architectural habit
• Flowers: Large white blooms with gold/yellow signals and violet markings; produced in flushes spring–autumn
  
• Seasonal Interest: Year-round evergreen structure; peak flowering spring–summer with spot blooms in autumn
• Wildlife Value: Nectar/pollen for insects; clumps offer shelter for small fauna
• Tolerance: Drought-tolerant (once established), heat-tolerant, wind-tolerant, coastal-tolerant; light–moderate frost (protect from hard frost); clay-tolerant with improved drainage
• Planting Density: Mass planting: 3–5 plants per m²; Edges/drifts: 2–3 plants per linear metre
• Pet Friendly: Generally non-toxic to pets; any plant ingestion may cause mild tummy upset

Where It Works Best

• Sunlight: Full sun to part shade (best flowering with sun)
• Soil: Well-drained loam or sandy loam; tolerates improved clay/raised beds; avoid waterlogging
• Water Needs: Establishment: 2 deep soaks/week for 8–12 weeks. Established: deep soak every 10–14 days in summer; monthly in winter if dry
• Maintenance: Mulch in spring; remove spent flower stems, comb or cut back tired foliage in late winter; divide clumps every 3–5 years; light feed in early spring
• Lifespan: 15-25 years
• Climate Zones: Suited to temperate and Mediterranean SA gardens, including coastal areas
• Soil pH: Acid, Neutral, Alkaline — adaptable

Landscape & Design Ideas

• Mass plant along paths, driveways and verges for a cohesive, low-maintenance finish
• Fill narrow beds and swales for year-round structure and seasonal colour
• Feature in large pots; pairs well with lomandra, grasses and gravel

Why You Will Love It

Fast, reliable and water-wise. Dietes grandiflora delivers months of big, showy blooms, tidy evergreen form and excellent heat/drought resilience — a high-value, low-effort performer for SA landscapes.