There are more than 2,000 plants in the species named euphorbia. Some euphorbia look like cacti, some trees and some spiny creepers; however, they are all in the Spurge family. The most recognized plant in the species are poinsettias, the popular Christmas annual. Other common plants are snow on the mountain and crown of thorns. Most euphorbias secrete a white milky substance that causes skin irritation when cut or when leaves are removed. Some of the plants, such as the crown of thorns, are poisonous when ingested. Euphorbias are grown with ease.
Fill a container within 2 inches of the top with a cactus/succulent soil for the euphorbias that imitate cactus. Add 1 part potting soil to 2 parts cactus soil for all others. Fast-draining soil is key to the health of all but one species, the E palustris, which will grow in wet soil.
Carefully remove the plant from the container you purchased it in and gently knock off the soil around the roots. Push away enough soil in the center of the pot to place the root ball of the plant. Firm the soil back around the root ball and tamp down.
Place the euphorbias in full sun. Read the label on your particular plant, as some in this species enjoy partial shade.
Water the plants once a week during the growing season. If it is particularly hot or dry, then the plant may need extra water. Hold back water during the winter, moistening the soil about once a month.
Feed the plants once a month with a water-soluble cactus/succulent fertilizer during their growing season. The growing season may be different for different plants within the species, so watch for growth and flowering. When the flowering stops, discontinue feeding until some growth begins again.
Cut off flower stalks when the flowers have died. This promotes more flowering and keeps the plant healthy. Euphorbias do not need any other pruning.