Rosemary ‘Blue Lagoon’

Rosemary 'Blue Lagoon' (Salvia rosmarinus) is a culinary rosemary that holds a proper shape, which most do not. It grows to roughly 1m tall and 1m wide, dense and upright, with narrow aromatic leaves and clear blue flowers through the cooler months. Clip it as a low hedge, edge a path with it, or keep one by the kitchen door and cut from it all year.

Why you'll love it

• Kitchen and garden in one plant. The same bush that edges the bed gives you rosemary for the kitchen all year.
• Blue flowers when the garden is quiet. Clear blue through the cooler months, working with bees when little else is open.
• It clips into a real low hedge. At 1m by 1m and planted 60cm apart it makes a tight formal edge, unlike the sprawling forms.
• Genuinely tough. Frost hardy, drought tolerant, happy in poor soil and salt tolerant enough for a coastal front garden.
• Safe around pets. Rosemary is not toxic to cats or dogs, so it can go in a bed the animals walk through.

Where it works best

Low hedging and edging. Plant 60cm apart for a clipped hedge around a vegetable patch or along a path. Two light trims a year hold it at knee to hip height with a solid base.

Coastal gardens and rockeries. Salt wind and thin, sharp draining soil are what this plant came from, so a rocky slope or an exposed front garden suits it better than a rich bed.

Pots. A pot 400mm or wider by the back door keeps it in reach for cooking, and container growing suits its dislike of wet roots.

Growing rosemary in Australia

Position and climate. Full sun, all day. It grows across Mediterranean, warm temperate, cool temperate, subtropical and arid gardens, which is most of the country. It is frost hardy. The one place it struggles is the wet tropics, where constant humidity brings on root and stem rot.

Soil. Sharp drainage is the whole game. It thrives in poor, gravelly, alkaline ground and dies in heavy wet clay, so mound the bed or use a raised bed if your soil holds water.

Water and feed. Water weekly for the first two months, then leave it be. Established plants need almost nothing outside a long drought. Skip the fertiliser: rich soil gives soft growth and weaker flavour.

Pruning. Trim lightly after flowering and again in late summer, never cutting back into bare old wood, because rosemary does not reliably reshoot from it. Regular light clipping keeps the plant dense for years.

What to expect when it arrives

It is sold as tube stock, so what arrives is a young plant, roughly a hand span tall, with a small root system. That is the standard way to buy rosemary, and there is no advantage in starting bigger: tubes root readily and catch up inside a season.

Plan on about 30 to 40cm of growth in the first year, with a clipped hedge line closing at 60cm spacing by the end of the second. Tubes travel well and are delivered Australia wide, delivery from $29.95, minimum order of $300 before delivery. Every plant carries our 30 day healthy plant guarantee.

Plant care guides and related reading

• Browse the full edible and herb range
• More plants for rockeries and dry slopes
• Salt tolerant plants for coastal gardens
• Other plants that are safe around cats and dogs

Common questions

Can I cook with it?

Yes. 'Blue Lagoon' is a culinary rosemary with the usual resinous, piney flavour. Cut sprigs from the outer growth rather than the centre, and the plant stays in shape while you harvest.

How far apart for a hedge?

Sixty centimetres apart in a single row. Any closer and airflow drops, which invites rot in humid summers, and the bases go woody and bare earlier than they should.

Why did my last rosemary die suddenly?

Almost always drainage. Rosemary tolerates drought far better than damp, and a plant that collapses over winter has usually been sitting in wet soil.