Crown of Thorns Mother of Pearl has large, 1-2 white flowers with pink petal edges and a pink blush as the flowers age. It creates a stunning floral show during the spring and summer blooming season. Euphorbias are indestructible houseplants that thrive on neglect. Be sure to let the soil dry out between waterings. This easy-care plant will thrive on a sunny windowsill or grow it outside during the warm summer months.