Heuchera 'Fire Alarm'

Fire Alarm Coral Bells / Heuchera

Botanical Name: Heuchera ‘Fire Alarm’
Family: Saxifragaceae
Origin: North America (garden cultivar selection)
Plant Type: Evergreen to semi-evergreen perennial (mounding, foliage-first)

Overview

A bold, shade-loving foliage plant with intense fire-red leaves that deepen to cherry/burgundy in cool weather. In Adelaide/SA it’s superb for part shade, dappled light and morning sun sites—bringing year-round colour to borders, underplanting and alfresco containers. Sends up fine wands of tiny pink-white bells in late spring–summer. Prefers free-draining, humus-rich soil and summer protection from hot afternoon sun.

Key Features

• Mature Size: 0.25–0.35 m H × 0.35–0.45 m W (foliage); flower stems to 0.45–0.6 m
• Growth Rate: 10-20 (spread) cm per year (clumps thicken over 12–18 months)
• Foliage: Large, glossy red leaves; colour intensifies in autumn/winter; may mute to red-bronze in summer heat
• Flowers: Fine wands of pink-white bells (late spring–summer); light, airy effect
  
• Seasonal Interest: Year-round foliage colour, strongest in cool seasons; summer bloom accents
• Wildlife Value: Flowers attract bees and beneficial insects
• Tolerance: Heat-tolerant with afternoon shade, light–moderate frost hardy; not drought-proof—prefers even moisture; second-line coastal OK (avoid salt winds); dislikes waterlogging
• Planting Density: Borders/edging: 3 per metre (≈30–40 cm centres); Mass: 6–9 plants/m²; Containers: 20–30 cm pots; size up as clumps thicken
• Pet Friendly: Generally non-toxic to cats & dogs (ingesting any plant may upset tummies)

Where It Works Best

• Sunlight: Morning sun/part shade to bright shade; avoid hot afternoon sun on the Adelaide Plains
• Soil: Free-draining, organic-rich loam; mix in compost/peaty organics. On calcareous SA soils, add organic matter; watch for iron chlorosis (treat with iron chelate if leaves pale)
• Water Needs: Establishment: 2-3 deep soaks/week for 8–12 weeks. Established: weekly deep soak in summer (twice weekly in heatwaves under eaves/pots); light in winter—don’t let pots dry out completely
• Maintenance: Remove spent flower stems at base; tidy old leaves late winter; mulch lightly (keep mulch off crowns). Liquid feed lightly in spring & early autumn (avoid heavy N). Divide every 3–4 years to rejuvenate and re-set crowns at soil level
• Lifespan: 5–7+ years with division/refreshing in SA conditions
• Climate Zones: Temperate & Mediterranean SA—best in Hills/dappled gardens and shaded Adelaide Plains sites; excellent in containers for control of drainage and heat
• Soil pH: Slightly acidic–neutral (tolerates slightly alkaline if organic-rich and well-drained)

Landscape & Design Ideas

• Alfresco pots and under-pergola planters for year-round colour
• Shaded borders with clivia, aspidistra, hellebore, ferns
• Contrast foliage in woodland/courtyard beds with blue/grey grasses or silvers (Artemisia, Stachys)
• Path edging where afternoon shade falls

Why You Will Love It

Unbeatable fire-red foliage that holds through the year in SA shade, with minimal fuss—just good drainage, afternoon-sun protection and steady summer moisture. Perfect for lifting shady beds and courtyards across Adelaide.