Hibiscus Tiliaceus 'Rubra'

Red Cottonwood / Cottonwood Hibiscus / Red Leaf Cottonwood

Botanical Name: Hibiscus tiliaceus 'Rubra'
Family: Malvaceae
Origin: Tropical Asia–Pacific (incl. northern Australia)
Plant Type: Evergreen tree/large shrub

Overview

Hibiscus tiliaceus ‘Rubra’ (Red Cottonwood) brings instant coastal vibe and year-round colour to South Australian gardens. Large, heart-shaped leaves emerge rich bronze-red to burgundy and mature to deep olive with a purple sheen. In warm months, classic hibiscus blooms open buttery yellow with a maroon throat, then age through orange to red before dropping—so the plant always looks “in flower.” Excellent as a fast screen, feature, or trimmed hedge; thrives in seaside, windy, and heat-exposed sites.

Key Features

• Mature Size: 3–6 m H × 3–5 m W
• Growth Rate: 40-80 cm per year under good conditions
• Foliage: Evergreen, large heart-shaped leaves; new growth copper/burgundy, maturing deep olive with plum tints
• Flowers: Summer–autumn; large yellow blooms with maroon centre, ageing orange → red; highly showy
  
• Seasonal Interest: Striking foliage year-round; peak floral display in the warmer months
• Wildlife Value: Drought-tolerant (once established), heat-tolerant, wind-tolerant, coastal-tolerant (frontline); light frost (protect from hard frost)
• Planting Density: Shrub borders/hedges: 1 plant per metre (dense) or 1 per 1.5 m for a looser effect
• Pet Friendly: Yes — generally non-toxic to cats/dogs; may cause mild stomach upset if large amounts are eaten

Where It Works Best

• Sunlight: Full sun to part shade
• Soil: Free-draining sandy or loam soils; tolerates poorer coastal soils if not waterlogged
• 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; light to hard prune after flowering or late winter to shape; fertilise in early spring
• Lifespan: 20-40 years
• Climate Zones: Ideal for temperate and Mediterranean SA gardens, including coastal areas
• Soil pH: Prefers slightly acidic to neutral; tolerates slightly alkaline coastal soils

Landscape & Design Ideas

• Fast coastal screen or boundary hedge; clip for a neat, burgundy-leaf backdrop
• Feature specimen near decks, pools and sunny courtyards for tropical drama
• Great in large pots (60 L+) for patios and entries; underplant with silver or lime groundcovers for contrast

Why You Will Love It

Big, bold foliage plus sunset-coloured flowers—‘Rubra’ delivers instant impact and fast privacy with minimal fuss. It shrugs off wind, salt and heat, making it a dependable hero plant for coastal and suburban gardens alike.