@susiwoo How long have you had the Euphorbia? What type of soil? And how much sun do they get roughly? Also worth checking if the soil is wet around the crown of the plant. Let me know and I'm sure we'll get something sorted.
Hi @susiwoo. This particular Euphorbia prefers a free draining soil in full sun so 18 months down the line it's struggling in its current position. A move to a better location will be best. Also, once the stems with flowers have finished flowering, they should be cut back at the base. Beware the milky sap though as it can be a skin irritant. Good luck Sue.