Cushion spurge

Cushion spurge: how do you recognise it?

Habit

A dense, rounded dome 30–40 cm tall and up to 60 cm wide.

Leaves

Oblong, up to 5 cm, soft dark green and sometimes slightly hairy; red to orange in autumn.

Flowers

Flat heads of sulphur-yellow bracts around tiny flowers, from April to June; after flowering the yellow fades to green.

Roots

A sturdy, somewhat woody rootstock: the plant slowly widens but does not run.

Sap

White milky sap in all parts, irritating to skin and eyes.

Flowering: April–June · Plants: March–April and September–October · Pruning: March and June

Why grow it?

• One of the brightest colours in the spring border: sulphur-yellow domes from April to June.
• Attractive in two seasons: in autumn the leaves turn red and orange.
• It forms a neat, rounded clump by itself, with no pruning or staking.
• Drought-tolerant and long-lived: it stays good-looking for years in the same spot.
• Early flowers for bees and hoverflies.

Cushion spurge: where does it grow best?

• Full sun or light partial shade; in sun the dome stays most compact and colours best.
• Sand, loam or clay, acid, neutral or chalky, as long as it drains well.
• Dry to normal soil; once established it copes well with drought.
• Give it 50–60 cm of space; it looks best as a single specimen or in a group of three at the front of the border.

Light

Sun and partial shade

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Dry or normal

Size

0.4 m tall, 0.6 m wide

Hardiness

Hardy (to -35 °C)

Goes well with

• Tulip: Red or purple tulips among the yellow domes make a vivid spring picture.
• Grape hyacinth: A blue carpet in April, right when the spurge is in flower.
• Pasque flower: Purple bells and silvery seed heads in the same dry, sunny spot.
• Bearded iris: Flowers in May–June and enjoys the same dry, sunny soil.
• Aubrieta: A low purple edging at the front of the border, also in April.

Cushion spurge: when and how to plant it?

Plant in March–April and September–October.

1. Plant in March–April or September–October.
2. Choose its final position straight away: older plants dislike being moved.
3. Wear gloves to protect yourself from the sap.
4. Dig a hole twice as wide as the root ball; in heavy clay, mix in some coarse sand or gravel.
5. Set the plant at the same depth as it was in its pot, firm the soil and space plants 50–60 cm apart.
6. Water in well straight away, and again in dry spells during the first year.

Care

Watering

In dry weather during the first year; after that only in very long dry spells.

Feeding

Not needed. A thin layer of compost in March is enough; rich soil makes the dome loose and floppy.

Mulching

A layer of gravel or a thin layer of compost; keep the crown itself clear.

Spent flowers

They can stay: they turn green. For fewer seedlings, shorten them in June.

Rejuvenating

An old plant that falls open in the middle can be cut back after flowering or replaced by a young cutting.

Tip: Just leave it alone: a cushion spurge that is left in peace forms a perfect dome by itself, year after year. If you want more, take cuttings in April rather than dividing.

Cushion spurge: when to prune it?

Pruning months: March and June.

When: Pruning is hardly needed. In March, cut away last year’s dead stems and, if you like, the spent stems in June.

How:

• In March, remove the dead, dried stems at the base before the new shoots appear.
• To avoid seedlings or keep the dome more compact, shorten the spent stems by a third in June.
• If an old plant falls open in the middle, cut the stems back by half after flowering: it will reshoot.
• Wear gloves, then wash your hands and your secateurs.

Caution: Do not cut it back in autumn: the red autumn colour is one of its great assets.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Cuttings

In April–May, take 6–8 cm cuttings from young shoots at the base. Dip the cut end in lukewarm water to stop the sap and insert in sandy cutting compost.

Seed

Sow the seed in summer as soon as it is ripe, in a pot outdoors. It also self-seeds a little.

Division

Possible with young plants in early spring, but old clumps with a woody base re-establish poorly after dividing.

Cushion spurge: how does it get through the winter?

Hardy to −35 °C.

• Extremely hardy, to about −35 °C: in Belgium it needs no protection.
• The stems die back in winter; in March new shoots appear at the base.
• Wet roots in winter are the main danger: make sure drainage is good.
• In a pot it simply overwinters outdoors, as long as water can drain away.

Diseases and pests

• Falling open: The dome splits apart in the middle, especially in shade or rich soil. Cut back after flowering and do not feed.
• Root rot: Yellow stems and a rotting base in wet soil. Move it to a drier spot or raise the bed with gravel.
• Aphids: Sometimes on young shoots in spring. Hose them off; natural predators will do the rest.
• Seedlings: In gravel or between paving, lots of young plants sometimes come up. Weed them out young or shorten the spent stems in June.

Through the year

• March: Remove dead stems. Plant. Thin layer of compost.
• April: The domes turn yellow: flowering begins. Take cuttings.
• May: Full flower. Bees on the flowers.
• June: Last flowers; the yellow turns green. Shorten spent stems if you wish.
• July: Collect and sow seed, or weed out seedlings.
• September: Plant.
• October: Red to orange autumn colour. Plant.
• November: The stems die back. Dormant.

Edible and useful

Not edible. All parts of spurges contain a white, milky sap that is poisonous and caustic. On the skin it causes redness, itching and sometimes blisters; in the eyes it is extremely painful and can damage the cornea. Whenever you work on the plant, wear gloves, long sleeves and ideally safety glasses, do not rub your eyes, wash your hands and secateurs afterwards, and teach children not to break off the stems. If sap gets in your eyes, rinse them at once under running lukewarm water for at least a quarter of an hour and see a doctor. Swallowed, it burns the mouth and causes vomiting and stomach ache, in dogs and cats too; horses and livestock fall ill from it: never throw clippings into a field. If any is swallowed, call a poison centre (in Belgium 070 245 245) or your doctor at once.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• The bright yellow does not come from petals but from the bracts around the tiny flowers: that is why the colour lasts for weeks.
• Polychroma, the old species name, means ‘many-coloured’: yellow in spring, green in summer and red in autumn.
• The Latin name Euphorbia honours Euphorbus, physician to King Juba II of Mauretania, some 2,000 years ago.