Sun spurge

How to recognise it

Growth habit

Annual of 10–50 cm, usually with a single upright, often reddish stem ending in a broad umbel. When broken it oozes white milky sap.

Leaf

Alternate, obovate to spoon-shaped, 1.5–3 cm, narrowed towards the base and finely toothed at the tip; yellowish to fresh green.

Flower

An umbel with five main rays, surrounded by a ring of five broad, yellow-green leaves; each ray branches further. The actual flowers are tiny and sit in little cups with oval, yellow nectar glands without horns. Flowers from April to October.

Fruit/Seed

A smooth, three-lobed capsule of about 3 mm with three brown seeds with a net-like pattern. Ripe fruits burst open and fling the seeds away.

Roots

A thin taproot; the plant comes up easily.

Confusion with

Petty spurge is smaller, has smooth-edged, untoothed leaves, an umbel with three rays and crescent-shaped glands with horns. Dwarf spurge has very narrow leaves. You recognise sun spurge by its five-rayed umbel with a ring of five broad, toothed leaves.

Flowering: April–October

Why grow it?

• Flowers for a long time, from April to October, with yellow-green umbels that give a little nectar to flies, small beetles, ants and small bees.
• The open nectar glands are easy to reach, even for short-tongued insects.
• A typical arable weed that shows how plants have lived alongside farming for centuries.
• Lovely up close: the five yellow-green leaves around the umbel form a real little crown.
• Easy to keep in check: annual and with a thin root, so quickly pulled up.

Sun spurge: where does it grow best?

• In the wild: fields, vegetable gardens, gardens, waste ground, verges and building sites.
• Sun to light shade.
• Rich, loose soil: loam, clay or sand that is regularly cultivated.
• In the garden: it appears by itself in the vegetable plot and in borders with bare soil; at most a spot in a cornfield-flower edge, away from children at play.

Goes well with

• Cornflower: A blue arable flower for a sunny field edge, far more valuable for bees and bumblebees.
• Common poppy: Red flowers on the same cultivated soil.
• Corn marigold: A yellow arable flower that blooms for a long time.
• Scented mayweed: White, fragrant flower heads, also a plant of fields and open ground.

Sun spurge: when and how to plant it?

1. There is no need to sow it: it turns up by itself on cultivated, rich soil.
2. If you want to keep it in a cornfield-flower edge, leave a few self-sown plants, far from where children play and pets roam.
3. Always wear gloves when pulling it up or moving it, and keep the sap away from your eyes.
4. If you want to keep it out, cover bare soil with mulch or a green manure and hoe off the seedlings.
5. Never take plants from the wild; for a cornfield-flower edge, sow native arable flowers with seed from a nursery instead.

Care

Water

Not needed.

Feeding

Not needed; on rich soil it actually grows more strongly.

Weeding

Pull or hoe out young plants before they flower and set seed, wearing gloves.

Letting it seed

If you let a few plants self-seed, bear in mind that the seed can lie in the soil for several years and keep germinating.

Disposal

Pulled plants without fruits can go on the compost heap; plants with ripe fruits go in the organic waste bin.

Tip: When in doubt, break a small stem: if white milky sap comes out, you have a spurge. Pull sun spurge in the vegetable garden with gloves on before the fruits are ripe, and you will have far less of it in the following years.

Pruning and mowing

When: Not needed; weed before it sets seed, from May to September.

How:

• No pruning needed: it is an annual that dies after setting seed.
• Pull up unwanted plants completely, wearing gloves, before the fruits are ripe.
• Cut off spent umbels if you want to limit self-seeding, but keep the sap off your skin.

Caution: Always wear gloves, and goggles for larger jobs: the sap irritates skin and eyes.

Pruning calendar and basic rules

Propagation

Seed

It self-seeds: ripe fruits burst open and fling the seeds away, and ants sometimes carry seeds further. The seed germinates mainly in spring and late summer on cultivated ground.

Sun spurge: how does it get through the winter?

Hardy to −20 °C.

• Most plants die off in late autumn; the seed overwinters in the soil.
• Seedlings that come up in late summer sometimes survive a mild winter and then flower early in spring.
• The seed can stay viable in the soil for several years.

Diseases and pests

• Milky sap: Irritating to skin and eyes. Wear gloves, wash your hands after work and never rub your eyes.
• Many seedlings: On cultivated soil it keeps coming back. Hoe early, on a dry day, and cover the soil with mulch.
• Pets: Rabbits and guinea pigs must not get it in their food. Weed it out near hutches and runs, and check any weeds you pick as feed.
• Confusion with wild greens: If you pick wild greens such as chickweed, take care: young spurge plants can grow among them. Break a stem: white milky sap means spurge.

Through the year

• March: The first seedlings appear on cultivated soil.
• April: First flowers. Hoe where you do not want it.
• May: Full bloom: flies and small beetles on the nectar glands.
• June: The first fruits. Pull up with gloves before they burst open.
• July: Flowering and setting seed. Weed in the vegetable garden.
• August: New seedlings after vegetables are harvested.
• September: Flowering continues. Sow a green manure on bare soil.
• October: Last flowers. Clear away plants.
• November: The plants die off; the seed overwinters in the soil.

Did you know?

• Helioscopia means ‘looking at the sun’: people used to believe that the umbels turned with the sun.
• The Dutch name kroontjeskruid, ‘little crown herb’, refers to the ring of five leaves around the umbel, which looks like a small crown.
• In folk medicine the caustic sap was once dabbed on warts; do not copy this, as it can damage the skin.