The blue potato bush (Solanum rantonnetti) is a tropical evergreen shrub that can grow to a height of several feet. A member of the nightshade family, the purely ornamental plant is poisonous. The potato bush has white, blue, lavender or bright purple flowers with yellow centres and berries. The prickly leaves on the potato bush can grow up to a foot long. The bush attracts bees, butterflies and birds. The potato bush grows in U.S. Department of Agriculture hardiness zones 9 through 11. You can care for a potato bush and maintain its shape for your landscape.
Plant the potato bush in an area with full sun exposure. The plant requires at least six hours of sunlight a day. Add compost to the soil to aid in drainage to prevent root rot. Cover the soil with a 3-inch layer of mulch to help maintain moisture in the soil.
Water the plant weekly on a regular schedule during the first year after planting. This helps the plant develop a deep, healthy root system. A consistently moist soil is best to maintain a healthy potato plant.
Fertilise the potato bush in the springtime before active growth starts. Use a general-purpose fertiliser that is water soluble. Follow product directions to fertilise the plant properly.
Prune the potato bush in early spring to shape it into a small tree shape if you want a more compact or formal plant in your landscaping. You can also allow it to grow freely into a large bush that you can shape as needed. Wear gloves and a long-sleeve shirt to protect your skin when pruning the bush. Remove dead and damaged branches and leaves before you shape the bush.
The potato bush can be grown in a container that is brought into a protective environment such as a warm garage or greenhouse during the cold weather season. The plant is deer resistant.
The berries that grow on the potato bush are mildly toxic with a bitter taste. Be aware that the sap of the bush is irritating to the skin.