Euphorbia leucodendron is called by several common names, including cat tails euphorbia, stick bush and pencil tree. That’s because of its upright, succulent branches, which make it resemble a small tree. You must grow Euphorbia leucodendron as a houseplant or an annual, except in U.S. Department of Agriculture plant hardiness zones 10 and 11, where it can live in the landscape. It is very sensitive to frost.
A spineless succulent, Euphorbia leucodendron puts out narrow, jointed stems that rise vertically, then outwards, to form a shrub. It reaches 4 to 6 feet tall and 3 to 4 feet wide in warm climates. In summer, the light-green foliage is topped with small, chartreuse cups holding tiny flowers. These are followed by small, red fruit. The stems of Euphorbia leucodendron bear tiny, brown scars where leaves have dropped.
Soil that has excellent drainage is best for Euphorbia leucodendron, so it is a good choice for containers in full sun. If planted in the ground, it prefers sandy loam. It doesn’t need much watering, and does fine in hot weather with a monthly soak. Soak potted plants more often. Euphorbia leucodendron also is deer resistant. Move the plant indoors as cooler weather approaches.
As a houseplant, Euphorbia leucodendron needs direct sun, so place it in a south- or west-facing window. Outdoors, it makes a strong vertical accent when mixed with other succulents in a container planting. In USDA zones 10 and 11, it can be planted as an evergreen, succulent hedge.
Like most euphorbias, Euphorbia leucodendron bleeds a sticky, white sap when cut. The sap can irritate skin and cause eye damage, and it may be toxic if eaten by animals or humans. Wear gloves and goggles when you prune or weed around the plant, and protect children and pets from encounters with it.