Commonly called spurge or milkweed, the Euphorbia is a genus comprised of over 2,000 diverse plants that thrive in tropical, subtropical and temperate areas around the world. The botanical genus includes weeds, flowering shrubs, semi-evergreen and deciduous trees, vines, cacti, herbaceous plants and succulents. While some varieties thrive as houseplants, other perform well outdoors as ground covers or in rock gardens. The tallest variety of Euphorbia is recorded at 70 feet, while the shorter varieties grow 4 to 5 inches in height.
Plant the desired variety of Euphorbia in well-draining soil exposed to six hours of direct sunlight every day. If container-growing the Euphorbia, select a pot 2 inches deeper than the root system of the plant and fill it with equal amounts compost, potting soil and sand. Ensure the container has at least one drainage hole.
Irrigate the Euphorbia every seven to 10 days, allowing the top 2 to 3 inches of soil to dry completely between watering. Water the potted Euphorbia deeply until excess water runs out through the drainage holes. Empty the saucer under the plant so it does not sit in water. Reduce watering to once a month in the winter, when the Euphorbia is dormant.
Feed the Euphorbia plant a well-balanced, water-soluble 10-10-10 fertiliser in spring, before new growth begins. Dilute the fertiliser to half the recommended strength before applying it around the base of the plant. Alternatively, use a fertiliser specifically formulated for succulents. Irrigate the plant deeply before feeding it.
Spray the Euphorbia plant with water during the summer.
Inspect the Euphorbia plants for pests such as mealy bugs, spider mites, fungus gnats and white flies. Treat infected parts with horticultural oil or spray infested parts with a jet of water from a hose to dislodge them. Snip off parts of the plant infested with fungal diseases to control spread, and treat with a registered fungicide according to package directions.
Wear protective gloves to take a cutting from the Euphorbia and propagate it. Take a healthy cutting from a branching point in spring. Hold the cutting under cold running water to stop the flow of milky sap. Do not plant immediately, but leave the cutting to dry for two weeks so it forms a callus over its cut end.
Grow the Euphorbia out of reach of children and pets. The milky sap it contains is extremely toxic and causes blisters in case of direct contact with eyes and skin. In case of contact, rinse the affected area immediately and call poison control services.