Rosmarinus Officinalis 'Blue Lagoon'

Rosemary 'Blue Lagoon'

Botanical Name: Rosmarinus officinalis 'Blue Lagoon'
Family: Lamiaceae
Origin: Mediterranean region
Plant Type: Evergreen shrub

Overview

Rosmarinus officinalis 'Blue Lagoon' is a compact, trailing rosemary that thrives in Adelaide and across South Australia’s Mediterranean climate. Masses of deep blue blooms cover the plant in late winter–spring, with spot-flowering through the year, bringing colour and pollinators when many shrubs are quiet. Tough, aromatic and beautifully textural, it spills over walls, edges paths, or fills sunny pots with ease.

Key Features

• Mature Size: 0.6–1 m H x 0.8–1.5 m W (naturally mounding/trailing)
• Growth Rate: 20-40 cm per year under good conditions
• Foliage: Fine, aromatic needle-like leaves; mid to grey-green with a silvery cast in heat/dry; fresh bright green new growth
• Flowers: Deep blue to violet-blue blooms mainly late winter–spring; intermittent flushes in autumn
  
• Seasonal Interest: Year-round evergreen structure with peak flowering in the cooler months
• Wildlife Value: Nectar-rich flowers that attract bees and other pollinators
• Tolerance: Drought-tolerant once established; Heat- and Coastal-tolerant; Light frost tolerant; Wind-tolerant; becomes Clay-tolerant in improved, free-draining soils
• Planting Density: Edges/low hedge: 2–3 plants per metre; Groundcover: 3–4 plants per m²
• Pet Friendly: Yes — pet-safe/non-toxic to dogs & cats

Where It Works Best

• Sunlight: Full sun (best flowering) to light part shade
• Soil: Well-drained loam, sandy loam or gravelly soils; avoid waterlogging. On heavy clay, improve with gypsum and coarse grit for drainage
• 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; prune after flowering or late winter to shape (avoid cutting into old wood); light organic feed in early spring
• Lifespan: 15-25 years
• Climate Zones: Suited to temperate and Mediterranean SA gardens, including coastal areas
• Soil pH: Neutral to Alkaline

Landscape & Design Ideas

• Low borders and pathway edging with a refined, cascading finish
• Mass plant for cohesive, weed-suppressing groundcover and low maintenance structure
• Spill over retaining walls and raised beds; feature near entries and outdoor living areas; excellent in larger pots

Why You Will Love It

Water-wise, aromatic and evergreen, ‘Blue Lagoon’ delivers a cascade of deep blue flowers in late winter–spring—prime colour when many plants rest. It thrives in Adelaide’s Mediterranean climate (including coastal sites), softening edges and spilling beautifully over walls and pots while feeding local bees. Long-lived and low maintenance, it gives you reliable structure and fragrance with minimal watering or pruning.