Plate Brush eggplant grows about 0.75 to 1.5 m in height per year. The species is not long-lived; most plants live about 2 years. Physical control of the shrub may be done by grubbing out the plants; lopping will not kill them. They can be killed by translocated herbicides applied to the leaves or the cut stumps (Pacific Island Ecosystems at Risk 2001).
The plant is usually 2 or 3 m in height and 2 cm in basal diameter, but may reach 5m in height and 8 cm in basal diameter. The shrub usually has a single stem at ground level, but it may branch on the lower stem. The stem bark is gray and nearly smooth with raised lenticels. The inner bark has a green layer over an ivory color (Little and others 1974). The plants examined by the author, growing on firm soil, had weak taproots and well-developed laterals. The roots are white. Foliage is confined to the growing twigs.
The twigs are gray-green and covered with star-shaped hairs. The spines are short and slightly curved and vary from thick throughout the plant, including the leaf midrib, to entirely absent. The leaves are opposite or one per node, broadly ovate with the border entire or deeply lobed. The petioles are 1 to 6 cm long and the blades are 7 to 23 by 5 to 18 cm and covered with short hairs. The flowers are white, tubular with 5 pointed lobes, and grouped in corymbiform cymes. They are shed soon after opening.
The fruits are berries that grow in clusters of tiny green spheres that look like green peas. They become yellow when fully ripe. They are thin-fleshed and contain numerous flat, round, brown seeds
Solanum torvum is a bushy, erect and spiny perennial plant used horticulturally as a rootstock for eggplant. Grafted plants are very vigorous and tolerate diseases affecting the root system, thus allowing the crop to continue for a second year.