The "Euphorbia tirucalli" or the "Pencil Cactus" is a member of the Euphorbia group of succulents. Another name for the plant is Milkbush because of the milky sap it discharges when harmed.  Highly ornamental, the Pencil Cactus will grow in a columnar upright fashion from 8 to 30 ft tall outdoors in a frost-free environment. It has pencil-thin stems that turn a fire-red colour during the colder months. It is a fabulous houseplant and makes an intricate silhouette in any space.  Care Instructions: Requires lots of bright sunlight Enjoys Low moisture levels Water every two to three weeks in the summer; no water is needed in the winter. In the fall and spring, reduce watering to every month. Any excess moisture needs to drain or be able to evaporate otherwise you risk root rot. Care Level Rating: Easy