Euphorbia resinifera

Resin spurge is a species that is native to Morocco and is found on the slopes of the Atlas Mountains. This plant has erect succulent stems that have the appearance of a cactus. The plant is a dense, slow-growing shrub forming a multi-stemmed, cushion-shaped clump that can grow 1 to 2 feet tall and spread 4 to 6 feet wide. The specific epithet, resinifera, means "resin-bearing" and references that the toxic sap that the stems exude when cut or damaged.  This plant belongs to the spurge family (Euphorbiaceae).

The resin spurge prefers full sun to partial shade and is tolerant of sandy and rocky soils. It requires well-drained soils and very little watering during most of the year. From spring to fall, water this plant when the top 1-inch of the soil feels dry, and reduce watering during the winter months.It needs just enough water to keep it from wilting. It is dry soils and drought tolerant, as well as, deer and rabbit resistant. It is winter hardy in USDA Hardiness Zones 9-11. It may be propagated by stem cuttings. The resin spurge branches profusely and stem segments are readily available. Allow stem segments (propagules) to dry for a week before planting so the wound can seal. Unsealed cuttings, planted too soon, will easily rot before they can grow roots.

Resin spurge has a stiff, mounding form with bluish to lime green stems. It is generally leafless with the stems providing photosynthesis. The ascending branches are pale green with four ridges, short, sharp spines and has small, inconspicuous flowers. The flowers are simple, and bright yellow, and flowering occurs along the ribs of the stems. It rarely flowers when planted outside of its native range. When the stems are damaged or cut, they exude a thick, milky  sap that is toxic.

The resin spurge may be used in warmer climates as border planting, container planting, or as an accent plant in a rock garden or drought tolerant garden. It is sometimes used as a houseplant.

Diseases, Insects, and Other Plant Problems: No significant insects or disease problems. Monitor for mealybugs, spider mites, and scale. Overwatering can cause root rot.

All parts of this plant are toxic. Keep children and pets away from this plant. Wear gloves to prevent contact with the toxic milky sap..

VIDEO Created by Laura Barth for "Houseplants, Succulents, and Cacti," a plant identification course offered in partnership with Longwood Gardens.

More information on Euphorbia.