Allow the soil to dry out completely between waterings. Euphorbia pyrenaica is drought-tolerant and prone to root rot if overwatered. Water thoroughly when the top few centimeters of soil are dry, ensuring good drainage.

Reduce watering significantly during the winter dormant period to prevent waterlogged conditions.

Prune in late winter or early spring before new growth begins. Remove any dead, damaged, or crossing stems. You can also prune to maintain shape or control size. Wear gloves, as the white sap can be an irritant.

Cut back leggy stems to encourage bushier growth.

Propagate by stem cuttings in spring or early summer. Take cuttings of 10-15 cm, dip the cut end in rooting hormone (optional), and allow the sap to dry for a day or two. Plant in a well-draining potting mix.

Cuttings root relatively easily with bottom heat and bright, indirect light.

Repot every 2-3 years or when the plant becomes root-bound. The best time to repot is in spring before the active growing season. Use a well-draining, gritty compost mix, such as a cactus or succulent blend.

Ensure the new pot has drainage holes to prevent waterlogging.