Euphorbia cyparissias aka Cypress Spurge

Euphorbia cyparissias, or cypress spurge, is in the spurge family. This plant has soft stems and lives for years. It comes from Europe and northwestern Turkey. People brought it to the United States for garden use. Its use in graveyards led to several common names. These names include graveyard weed and graveyard ground pine. It now grows outside gardens in many regions.

Plants form dense patches of stems that stand and branch. Garden plants often reach 0.75–1 foot [0.23–0.3 metres] tall. RHS gives an upper height of 1.6 feet [0.5 metres]. Small clumps span about 1–1.5 feet [0.3–0.46 metres]. RHS records spreads reaching 5 feet [1.5 metres]. Thin green stems are smooth and have no hairs. Soft, narrow, blue-green leaves give it a small cypress-like shape. Lower leaves grow in turn along the stem. Upper leaves may grow in rings called whorls. The plant sheds its leaves, which can turn red in autumn.

Flowers crowd the stem tips from April to June. The tiny true flowers lack petals and sepals. Bright yellow-green bracts, or changed leaves, give most of the colour. These turn orange or red as they age. Groups of them stand above the fine leaves. Bees and other insects visit the flowers. Seed pods with three lobes then form. Each holds up to three small, smooth, grey seeds.

Cypress spurge grows best in full sun with good drainage. It copes with drought and poor, sandy or stony ground. It also grows in clay and at varied soil pH levels. Sources describe both dry and moist soils that drain well. Rich, moist soil can make its spread hard to curb. Missouri Botanical Garden lists USDA zones 4–8. RHS rates it H7. It covers the ground on dry banks and sunny slopes. Yet its rhizomes, or spreading underground stems, can overwhelm nearby plants. The many seeds it sheds can do this too. Several US states class it as invasive or noxious. It can be hard to remove by hand.

Serious pest and disease problems are rare, though rust may occur. RHS says to cut stems to ground level in early spring. You can raise new plants from seed or by division. All parts cause harm when eaten, including to pets and livestock. Broken stems and leaves release a milky sap. This can inflame skin and cause serious eye damage. Swallowing plant parts can cause blisters on the mouth and lips. Wear gloves and eye protection when you handle the plant. Keep it away from children and pets.