Euphorbia myrsinites aka Myrtle Spurge

Euphorbia myrsinites, or myrtle spurge, is an evergreen perennial. It belongs to the spurge family, Euphorbiaceae. Its native range runs from southern Europe to northern Iran. It grows in rocky ground and grassy sites there. Garden plants have escaped into parts of North America. Several western US states list it as a noxious weed.

This low plant forms a mound with trailing stems. Most accounts place its height at 0.3–0.7 feet [0.1–0.2 metres]. One source gives an upper height of 1 foot [0.3 metres]. Its spread can reach 2 feet [0.6 metres]. A woody base rests near the ground. Leafy stems trail out, then turn upward at their tips. Fleshy, oval leaves crowd the stems in tight spirals. Their blue-green, waxy surface gives the plant a pale cast. The leaves end in points and remain through winter.

Flowers appear from March to April on second-year stems. The small, greenish-yellow flowers draw little notice on their own. Bright yellow bracts around them supply most of the colour. Blue-green capsules follow, each holding three brown, pitted seeds. Ripe capsules can fling seeds 15 feet [4.6 metres]. Seedlings can spread far beyond the parent plant. Remove spent flower heads promptly to limit unwanted seedlings. Established escapes can prove hard to control.

Grow myrtle spurge in full sun with good drainage. It suits dry ground and withstands drought and poor soil. Sandy and rocky soils suit it, but other textures work with drainage. It accepts acid, neutral, and alkaline conditions. Sources give USDA ranges of 4–8 and 5–9; RHS rates it H5. Cold winds can spoil the leaves despite their evergreen habit. Warm winters can shorten its life. Use it at border edges, in pots, or among rocks. Its stems can trail over stone walls. Deer and rabbits tend to leave it alone.

Serious pest and disease trouble is uncommon in suitable conditions. Watch for aphids, mealybugs, and leafy spurge flea beetles. Wet soil can lead to fungal or bacterial rot. All parts contain milky sap that can harm skin and eyes. Eye contact can cause lasting damage. Eating the plant can blister the mouth and lips. It is harmful to people and pets, not a food plant. Wear protective gloves when handling it. Keep it beyond the reach of children and pets.