Lycianthes rantonnetii’s sweetly scented blossoms known as Paraguay nightshade potato bush and Solanum rantonnetii, provide a focal point to a cottage or subtropical tropical garden. Surrounded by other sun-loving subtropical and tropical perennials, annuals and bulbs, the shrub blossoms yearlong in gardens that are frost-free. Native to Argentina and Paraguay, the blue potato bush is hardy in U.S. Department of Agriculture hardiness zones 9 to 11.
Pick a sunny place at least 4 feet from fences and walls, in the garden. The blue potato bush grows up to 8 feet tall and equally wide unless pruned to a tree-shaped form.
Dig a pit three times the diameter of the main ball. Remove in the grower’s pot and gently place into the pit. Backfill with the excavated soil, tamping softly.
Water thoroughly after planting the blue potato bush. Allow the soil to dry to a depth of two inches before watering. Allow water until the soil is moist to gradually trickle over the root ball. Slowly add water until it drains from the bottom of the pot if the bush is planted in a large flowerpot or bathtub.
Add a 4-inch layer of compost around the blue potato bush, yanking on it down 4 inches. Mulch keeps the soil evenly moist and discourages weed growth.
Fertilize in spring with a liquid 10-10-10 fertilizer based on the instructions of the manufacturer. Fertilize monthly In case your potato bush is planted in a bathtub.
Prune following the blue potato bush or from the early fall has stopped blooming. Shape the bush to a shrub, tree or”lollipop.” Eliminate to one third of every branch to maintain the form that is desired.
Monitor the blue potato bush for insects like thrips and aphids. Remove aphids with a solid stream of water in the morning so the leaves are dry before nightfall. Manage thrips by spraying on on the shrub with a horticultural oil, neem oil or a product.