Put on a pair of latex gloves before cutting the Euphorbia enopla plant since it bleeds white sap that will cause skin irritation and discomfort if touched.
Cut a 4- to 6-inch-long section from the tip of a healthy Euphorbia enopla stem in early summer. Make the cut with pruning shears. Handle the cutting with a pair of tongs to protect your hands from the sharp spines.
Run water from a garden hose over the end of the cutting to staunch the flow of sap. Place the cutting in a dry, shady location for seven to 10 days to allow the cut to callus over.
Fill a 5-inch plastic pot to the halfway point with a mixture of equal parts perlite and coarse sand. Set the Euphorbia enopla cutting inside the pot with the cut-end resting on the surface of the perlite and sand mixture. Fill the pot around the cutting with more of the perlite and sand mixture until the cutting is halfway buried. Water it with 1/2 cup of water.
Place the potted Euphorbia enopla cutting near a well-lit window or outside in a protected spot when temperatures stay reliably above 50 degrees Fahrenheit at night and 70 degrees Fahrenheit during the day. Check for root growth after 20 days.
Harvest seeds from a healthy Euphorbia enopla plant in late summer when the flowers have faded and formed into seed heads. Snip the seeds loose using pruning shears and remove the seeds from their husks. Set the seeds aside.
Combine equal parts perlite, coarse sand and potting soil to create a good rooting mix for Euphorbia enopla seeds. Fill several 5-inch plastic pots with the mixture and saturate it with water. Drain it for five minutes or so before sowing the seeds.
Scatter the Euphorbia enopla seeds over the surface of the soil and press them slightly with the flat of your thumb to anchor them. Scatter a thin layer of sand over the top to keep them from drying out or accidentally blowing away.
Place the potted Euphorbia enopla seeds on a propagation heat mat set to 75 degrees Fahrenheit near a source of bright light. Drizzle 3 or 4 tbsp. of water across the soil every other day to keep the soil mixture moist but not saturated.
Check for signs of germination after 20 days. Gradually lower the temperature of the propagation heat mat by increments of 5 degrees daily until the temperature matches the ambient air temperature. Turn off the mat.
Keep the potted Euphorbia enopla seedlings indoors until the following spring. Move them outside to a sheltered spot once all danger of frost has passed. Repot them into larger pots or plant them in a permanent outdoor bed once they establish a good root system and begin to put on growth.