Coastal Rosemary 'Zena' / Native Rosemary 'Zena'
Botanical Name: Westringia hybrid ‘Zena’
Family: Lamiaceae
Origin: Australia
Plant Type: Evergreen shrub
Overview
‘Zena’ is a compact and reliable Westringia selection ideal for Adelaide and coastal SA. It forms a dense, neat shrub with fine grey-green foliage, naturally rounded in shape, and soft pale lilac to mauve flowers that appear for long stretches of the year. Exceptionally hardy, it thrives in heat, wind and salt, making it a perfect fit for Mediterranean and coastal gardens.
Key Features
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Mature Size: 1–1.5 m H × 1-1.5 m W (kept smaller with light clipping)
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Growth Rate: 20-40 cm per year under good conditions
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Foliage: Narrow, rosemary-like grey-green leaves; compact, fine-textured habit
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Flowers: Soft pale mauve to lilac, heaviest in spring and autumn with intermittent flowers in other seasons
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Seasonal Interest: Evergreen structure with extended bloom periods
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Wildlife Value: Attracts native bees and butterflies; dense branching offers shelter for small birds and beneficial insects
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Tolerance: Drought and heat tolerant once established; excellent salt & wind tolerance; light frost hardy; happy on sandy or limestone soils if well-drained
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Planting Density: Hedge: 1 plant per metre (0.7 m for very tight screens); Specimen/mass: 1.2–1.5 m apart; Groundcover edge: 2–3 plants per m² for a clipped, continuous look
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Pet Friendly: Generally non-toxic; discourage chewing of any ornamental plant
Where It Works Best
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Sunlight: Full sun to part shade (more sun = tighter form & heavier bloom)
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Soil: Well-drained loam, sandy loam or improved clay; avoid chronic waterlogging
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Water Needs: Establishment: 2 deep soaks/week for 8–12 weeks. Established: deep soak every 10–14 days in summer (more in heatwaves); monthly in winter if dry
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Maintenance: Tip-prune after flowering or light clip 2–3×/yr to keep hedges crisp and promote new flowers; mulch in spring; feed lightly in early spring (native-safe, low-P fertiliser if planting with natives)
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Lifespan: 15-20 years
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Climate Zones: Suited to temperate and Mediterranean SA gardens, including coastal areas
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Soil pH: Slightly acidic to alkaline; performs well on Adelaide limestone
Landscape & Design Ideas
- Polished hedges and borders along driveways and paths—holds straight lines with minimal trimming and brings long seasons of mauve colour
- Coastal & poolside planting: thrives in salt spray and wind; pair with lomandra, dianella, olives and blue/grey succulents for a modern Mediterranean/native palette
- Large pots and troughs flanking entries or framing outdoor rooms—clean form and extended flowering for year-round appeal
Why You Will Love It
‘Zena’ delivers soft lilac blooms for much of the year on a shrub that’s unfazed by Adelaide heat, wind and coastal conditions. It stays neat with just a couple of light clips annually, attracts pollinators, and provides dependable, evergreen structure that instantly elevates garden appeal.
