Euphorbia glauca - Spurge

The Euphorbia glauca is an endemic species of the coasts of New Zealand, ideal in seaside gardens or well-drained soils of a rockery. It is a perennial cultivated for ornamentation due to the bright blue-grey color of its evergreen foliage, which contrasts wonderfully with its red stems and winter flowering in terminal cymes with deep red and purple bracts. This plant forms a clump of creeping and then erect stems up to 1m (3ft) high which effectively cover difficult terrain and form dense bluish borders. It is easy to grow in full sun or partial shade in well-drained soil, even dry, but it thrives better in cooler conditions.  

The Euphorbia glauca belongs to the vast family of euphorbiaceae. It is the only representative species of the genus that is endemic to New Zealand. In its native habitat, it grows along the coasts on cliffs, dunes, slopes, and shores in rocky to sandy soil. It is a plant that withstands drought well but prefers a soil that is not too dry, very well-drained.

The Euphorbia glauca is a rhizomatous perennial plant that develops from a creeping stem, producing numerous stolons that allow it to colonise the soil. Its stems tend to elongate and become bare at the base, so prune it every year after flowering to maintain a compact habit. It reaches about 1m (3ft) in all directions. The plant has a wide and spreading habit with numerous upright, brightly colored red stems. They enhance its narrow, oblong evergreen foliage, 12cm (5in) long, forming compact whorls of bright blue-grey, sometimes pastel green. The flower stems appear between October and February, in umbels of petal-less flowers surrounded by a deep red cup, surrounded by purple bracts. The stems and leaves contain a milky sap that is sticky and toxic.

The Euphorbia glauca will find its place in a dry and sunny rockery, on a wild slope where it will not suffocate its neighbors. Indeed, it can be an invasive plant. It can be associated with other formidable ground covers such as Achillea crithmifolia, Stachys byzantina Big Ears, Georgia Blue speedwell, and Artemisia canescens. It will form beautiful patches of color at the base of bushes, dark-foliaged plants: 'Black Lace' elderberry, Berberis thunbergii Atropurpurea, purple sage, tall sedums like 'Black Jack' or 'Chocolate'. Its aniseed flowering goes well with the blue of creeping rosemary and perennial flax.