The African milk tree, Euphorbia trigona, grows like a living candelabra: upright three-sided stems lined with small leaves and short spines, branching as it matures into a sculptural column that can reach ceiling height indoors over the years. It looks like a cactus but is actually a succulent euphorbia.

Give it a bright window, water only when the soil is fully dry, and use a fast-draining cactus mix. Keep it above 60 degrees and away from drafts. Wear gloves when pruning, since the milky sap irritates skin. Otherwise it asks almost nothing of you.