Euphorbia hyberna (Irish spurge) — Clump-forming, upright or spreading sub-shrub

Overview

Euphorbia hyberna is a clump-forming, upright or spreading sub-shrub perennial in the genus Euphorbia, part of the Euphorbiaceae family, with evergreen, semi-evergreen or deciduous; narrow, often blue-grey or glaucous, sometimes red-tinted in autumn foliage. Euphorbia hyberna grows best in full sun to partial shade; the woodland species tolerate dry shade, and tolerates light to moderately fertile loam and sand or chalk soils and acid and neutral or alkaline pH. Its UK hardiness is rated H4-H7. Suggested uses include woodland gardens, shaded borders and naturalistic plantings.. It is native to Ireland.

About

Euphorbia hyberna is a clump-forming perennial spurge from Ireland with narrow, often blue-grey (glaucous) leaves that may take a red tint in autumn. It grows as an upright or spreading sub-shrub and can be evergreen, semi-evergreen or deciduous depending on conditions. Flowering occurs from May to September. Take care when pruning or handling as the milky sap is a skin and eye irritant.

About the genus

Euphorbia is a large and diverse genus of flowering plants, commonly called spurge, in the family Euphorbiaceae.

Wikipedia contributors, "Euphorbia", CC BY-SA 4.0 — Euphorbia

In the garden

Euphorbia hyberna is a perennial member of the Euphorbiaceae, native to Ireland and carrying the compact, clump-forming habit of a small sub-shrub. Its narrow, frequently glaucous leaves persist through much of the year on plants that range from evergreen to deciduous, and it produces flowers between May and September. The combination of glaucous foliage and autumn red-tinting gives the plant seasonal colour without relying on large blooms. Sit plants in full sun to partial shade; populations from woodland sites tolerate dry shade and are well suited to areas with reduced light. It prefers light to moderately fertile loam, sand or chalk and will grow on acid, neutral or alkaline soils provided they drain freely — most specimens dislike winter wet. The species is rated H4–H7, meaning it ranges from average hardy to fully hardy in UK terms, and will tolerate either exposed or sheltered positions and any garden aspect. Use Euphorbia hyberna in woodland gardens, shaded borders or naturalistic plantings where a narrow-leaved, long-lived ground cover is needed. Avoid waterlogged hollows and plant with companions that accept dry, well-drained soils. Wear gloves and eye protection when cutting or dividing since the milky sap can irritate skin and eyes; leaves commonly develop a red tint in autumn so minimal intervention preserves seasonal character.

Growing conditions

Best soil and position for Euphorbia

Sunlight: Full sun to partial shade; the woodland species tolerate dry shade
Soil type: Light to moderately fertile loam, sand or chalk
Soil pH: Acid, neutral or alkaline
Soil moisture: Well drained; most dislike winter wet
Aspect: Any
Exposure: Exposed or sheltered
UK hardiness: H4-H7

Plant details

Euphorbia hyberna size, habit and characteristics

Plant type: Perennial
Habit: Clump-forming, upright or spreading sub-shrub
Foliage: Evergreen, semi-evergreen or deciduous; narrow, often blue-grey or glaucous, sometimes red-tinted in autumn
Suggested uses: Woodland gardens, shaded borders, naturalistic plantings.
Native to: Ireland
Toxicity: The milky sap is a skin and eye irritant.

Care notes

Pruning and caring for Euphorbia hyberna

Cultivation: Easy and largely self-sufficient given drainage. The milky sap is a genuine irritant to skin and eyes, so wear gloves and eye protection when cutting back and never handle the plant in strong sun. Most flower on stems produced the previous year, which makes correct timing of the cut essential. The spreading species can be invasive in loose soil, so site them accordingly.
Pruning: On the shrubby evergreen kinds, cut flowered stems right to the base once the bracts fade in summer, leaving this season's new shoots to flower next year. Cut herbaceous species down in late autumn.
Propagation: Divide herbaceous kinds in spring. Take basal cuttings of shrubby species in spring and rinse the cut end to stop the latex sealing it. Many self-seed freely.
Pest resistance: Rarely troubled by pests; aphids occasionally gather on soft new growth.
Disease resistance: Generally healthy. Euphorbia rust causes orange spotting and distorted shoots on some species and affected growth should be removed.

Frequently asked questions

How do I grow Euphorbia hyberna?

Easy and largely self-sufficient given drainage. The milky sap is a genuine irritant to skin and eyes, so wear gloves and eye protection when cutting back and never handle the plant in strong sun. Most flower on stems produced the previous year, which makes correct timing of the cut essential. The spreading species can be invasive in loose soil, so site them accordingly.

Where is the best place to plant Euphorbia hyberna?

Euphorbia hyberna prefers full sun to partial shade; the woodland species tolerate dry shade. It suits exposed or sheltered positions.

What soil does Euphorbia hyberna need?

Euphorbia hyberna grows best in light to moderately fertile loam and sand or chalk soil. It prefers acid and neutral or alkaline soil. Aim for soil that stays well drained; most dislike winter wet.

How do I prune Euphorbia hyberna?

On the shrubby evergreen kinds, cut flowered stems right to the base once the bracts fade in summer, leaving this season's new shoots to flower next year. Cut herbaceous species down in late autumn.

Is Euphorbia hyberna hardy in the UK?

Euphorbia hyberna has an RHS hardiness rating of H4, meaning it is hardy through an average UK winter, tolerating -10 to -5°C.

How do I propagate Euphorbia hyberna?

Divide herbaceous kinds in spring. Take basal cuttings of shrubby species in spring and rinse the cut end to stop the latex sealing it. Many self-seed freely.

Is Euphorbia hyberna toxic?

The milky sap is a skin and eye irritant.

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