Grow the Euphorbia epithymoides in full sun. It will tolerate some shade, but the coloring won't be as vibrant.
Water the euphorbia only during periods of drought that last longer than three weeks. When you do water, soak the soil slowly to a depth of 10 inches. A soaker hose is ideal for this purpose.
Fertilize the E. epithymoides in spring, as soon as you notice new growth. Use a 10-10-10, or any balanced fertilizer, at the rate listed by the manufacturer for the size of your shrub. Spread the fertilizer over the soil around the plant and water as per usual.
Prune the euphorbia by cutting all the stems back to one-third of their length. Wait until after it finishes flowering to prune it and wear gloves to avoid skin irritation from the sap that leaks after pruning.
Spray the Euphorbia epithymoides with insecticidal soap to deal with pest infestation. Aphids, mealy bugs and spider mites are attracted to the plant. Don't spray during the hottest part of the day to avoid burning the foliage.