CARE of Crown of thorns (Euphorbia):

It is a shrubby succulent with long stems covered with long sharp thorns and thick fleshy leaves. The leaves remain on the plant for several months before eventually falling off. The red flower heads consist of two thick bracts. The flowering period usually falls between the beginning of spring to the end of summer, but in good conditions and a lot of light the plant can flower all year round.

Likes to be in a sunny warm place where the temperature does not drop below 15°C.
Requires a dry to normally moist soil, let the pot dry between waterings before watering. During the growing period, from April to September, give plant food once every fortnight. Dislikes changing temperatures, too much or too little water or moving the plant. The plant can be pruned annually in March/April to maintain a compact shape.