Few spring perennials shout as loudly as Euphorbia polychroma, whose neat domes erupt into a haze of acid-yellow bracts just as the tulips hit their stride. Reliably tidy, drought-tolerant and long-lived, it forms a rounded cushion roughly 40 cm high that needs almost no attention once settled. Its most distinctive trait is a second act: the foliage often flushes copper, orange or red in autumn, giving two seasons of colour from one plant.
Cushion spurge is at its best in full sun, where it builds a dense, self-supporting dome and colours strongly in autumn. It will accept two or three hours of shade a day, but deeper shade causes stems to stretch, flop outwards and open up in the centre. Choose an open position with good air movement rather than a damp, enclosed corner.
Drainage matters far more than fertility. This is a plant of dry, stony grassland in central and southern Europe, so it thrives on sandy loam, chalk, gravel and even thin poor soils, whilst heavy wet clay in winter is its main enemy. A neutral to alkaline pH suits it best, though it copes with slightly acidic ground provided water drains freely.
Once established it is genuinely drought-tolerant and shrugs off cold to around −20 °C, making it dependable across most of the UK, northern Europe and North American zones 4 to 9. In high-rainfall western gardens, plant on a slight mound or raised bed to keep the crown dry.
Spring, from March to May, is the ideal planting time: the soil is warming, roots establish quickly and you see the flowering display straight away. Early autumn planting also works well on light, free-draining ground.
Always wear gloves when handling euphorbias. The white latex sap is a skin and eye irritant, so avoid touching your face and wash any splashes off promptly.
Cushion spurge asks for very little, but the little it asks falls at precise moments in the year. This table sets out what the plant is doing and the one job that matters in each season.
| Season | What the plant is doing | Key task | Water and feed |
|---|---|---|---|
| Early to mid-spring | New shoots push up, often flushed red, and flowering begins | Divide congested clumps now if needed, accepting plants may sulk for a season | A light scattering of general-purpose fertiliser or a thin compost mulch around, not over, the crown |
| Early summer to midsummer | Bracts fade from acid-yellow to green | Shear the whole plant back by about a third to keep it compact and stop self-seeding | Water only in prolonged drought; avoid feeding, which encourages lax growth |
| Autumn | Foliage flushes red, orange and bronze | Leave the foliage to colour, then cut stems to about 5 cm once they blacken after the first frosts | No feeding; refresh gravel mulches if you use them |
| Winter | Dies back completely to a woody crown | No protection needed; make sure winter wet cannot collect around the base | None; a handful of grit over the crown helps on heavy soils |
Read across a single row and you have the whole year’s work: one shear, one cut-back, and otherwise leaving the plant alone.
Spring: New shoots appear early, often flushed red, and flowering begins in April. A light scattering of general-purpose fertiliser or a thin mulch of garden compost around — not over — the crown is all the feeding required. Divide congested clumps now if needed, though plants dislike disturbance and may sulk for a season.
Summer: Once the bracts fade to green in June or early July, shear the whole plant back by about a third to keep it compact and prevent self-seeding. Water only in prolonged drought; overwatering causes far more losses than dry soil. Avoid feeding, which encourages lax growth that splays open.
Autumn: Leave the foliage in place to enjoy the red, orange and bronze autumn tints, which can rival any small shrub. Cut stems down to about 5 cm once they blacken after the first frosts, and clear the debris to reduce fungal spores. Refresh gravel mulches now if you use them.
Winter: The plant dies back completely to a woody crown and needs no protection in most climates. Simply ensure winter wet cannot collect around the base — a handful of grit over the crown helps on heavy soils.
The straight species holds an RHS Award of Garden Merit, but several selections add foliage interest.
