How to Grow Westringia Rosemary 'Blue Gem'
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Westringia Rosemary 'Blue Gem'
Westringia fruticosa 'Blue Gem'
shrubBlue Gem is a compact, ornamental shrub native to Australia that resembles rosemary with fine, needle-like foliage and prolific blue-purple flowers. It is a hardy, drought-tolerant plant ideal for Mediterranean-style gardens, containers, and coastal landscapes. The plant blooms almost year-round in warm climates and attracts pollinators.
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Example Westringia Rosemary 'Blue Gem' timeline · Pittsburgh, PA (Zone 6b)
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Plant Westringia Rosemary 'Blue Gem'
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Westringia Rosemary 'Blue Gem'
Late summer into fallBefore the first fall frost (≈ Nov 8)
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Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 9b-11, tolerates zone 9a with protection
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Get my Westringia Rosemary 'Blue Gem' timeline →Growth Stages
Establishment
4-8 weeksYoung transplant with sparse foliage and minimal flowering; roots establishing in soil
Water regularly but allow soil to dry between waterings; avoid waterlogging; stake if needed in windy locations; apply light mulch away from base
Vegetative Growth
2-4 monthsPlant develops denser, bushy habit with fine needle-like leaves; minimal flowering
Prune lightly to encourage branching and compact form; reduce watering as roots deepen; apply balanced fertilizer sparingly if desired
Early Flowering
1-2 monthsFirst flower buds appear along stems; small clusters of blue-purple flowers emerge
Continue established watering schedule; do not overwater during this phase; light phosphorus-rich feeding can encourage more blooms
Peak Blooming
2-6 months (can be almost year-round in warm climates)Profuse blue-purple flowers cover much of the plant; plant reaches mature size and full ornamental appeal
Minimal watering needed; deadhead spent flowers to encourage continuous blooming; avoid excessive pruning during peak season
Maintenance
OngoingEstablished mature shrub with regular flowering cycles; plant is fully hardy and independent
Prune after main flowering to maintain shape; water only during drought; no fertilizer needed; pest monitoring as needed
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Increase humidity with occasional misting; spray with water to dislodge; use insecticidal soap if severe; ensure good air circulation
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Use yellow sticky traps; spray with neem oil or insecticidal soap; encourage natural predators like lacewings
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Remove by hand or soft brush; apply horticultural oil in dormant season; prune heavily infested branches
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Improve drainage immediately; reduce watering; repot if in containers; remove affected roots and replant in fresh, dry soil
Uses
Garden ornament and landscaping
OrnamentalBlue Gem is an excellent ornamental shrub for Mediterranean, xeriscape, and cottage gardens. Its fine foliage and prolific blue-purple flowers add color and texture year-round in warm climates. [source]
Pollinator attraction
WildlifeThe abundant flowers attract bees, butterflies, and other beneficial insects, making it valuable for pollinator gardens and supporting local ecosystems. [source]
Cut and dried flowers
HouseholdThe long-lasting flowers work well in fresh floral arrangements and can be dried for dried flower crafts, wreaths, and decorative purposes. [source]
Container gardening
HouseholdIts compact, dense habit and low maintenance needs make it ideal for growing in pots and containers on patios, balconies, and coastal gardens. [source]
Culinary herb (optional)
CulinaryWhile not commonly used, Westringia leaves have mild aromatic properties similar to rosemary and can be used sparingly in teas or as a garnish, though culinary use is secondary to its ornamental value. [source]
Harvest Tips
Westringia Blue Gem is grown as an ornamental shrub, not typically harvested for culinary or medicinal purposes. Deadhead spent flowers regularly to encourage continuous blooming. Prune in spring or after peak flowering season to maintain shape and promote denser growth. Cut branches can be used in fresh or dried floral arrangements.
Fun Facts
- 🌱 Westringia fruticosa is native to southeastern Australia and is commonly called 'Coastal Rosemary' because its appearance closely resembles true rosemary, though they are not closely related botanically.
- 🌱 Blue Gem can bloom nearly continuously throughout the year in warm climates (zones 10-11), providing almost year-round color and nectar for pollinators.
- 🌱 This plant is extremely salt-tolerant and performs well in coastal gardens with salt spray, making it ideal for seaside landscapes where many other plants struggle.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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