The Giant Potato Tree, Solanum wrightii, is a striking ornamental plant known for its rapid growth and abundant, showy flowers. It brings an exotic, tropical flair to any garden, making it a popular choice for those seeking a dramatic botanical statement.
Understanding the Giant Potato Tree
The Giant Potato Tree, Solanum wrightii, is distinct from the edible potato (Solanum tuberosum) despite its common name; it does not produce edible tubers. Both plants belong to the Solanaceae family. Native to tropical South America, Solanum wrightii thrives as an evergreen shrub or small tree.
This species grows rapidly, often reaching 4.5 to 9 meters (15 to 30 feet) in height and spread. Its trunk features light gray, fissured bark and can bear sharp thorns, while its foliage consists of large, deeply lobed, hairy leaves up to 30 cm long. The most notable feature is its large, star-shaped flowers, 6.5 to 7.5 cm (2.5 to 3 inches) wide. These blooms initially appear vibrant dark purple, gradually fading to light purple and white over several days, creating a multi-hued display.
Growing Conditions and Care
Light Requirements
For optimal growth and abundant flowering, the Giant Potato Tree thrives in full sun exposure. While it tolerates some light shade, consistent direct sunlight promotes vigorous blooming. Place the plant where it receives at least six hours of direct sun daily to support its growth and maximize its ornamental appeal. Adequate light also contributes to healthy, dense foliage.
Soil and Potting
This species prefers fertile, well-draining soil rich in organic matter. Incorporating compost into the planting area or potting mix provides nutrients and improves drainage. If growing Solanum wrightii in containers, select a large pot, at least 30 cm (12 inches) in diameter, to accommodate its vigorous root system. Ensure the container has ample drainage holes to prevent waterlogging.
Watering Needs
The Giant Potato Tree requires moderate, consistent watering for healthy growth. Water regularly, allowing the top layer of soil to dry slightly between waterings to prevent root saturation. Applying mulch around the plant’s base helps conserve soil moisture, reduces evaporation, and regulates soil temperature.
Temperature and Humidity
Originating from tropical climates, Solanum wrightii prefers warm temperatures and is sensitive to frost. In regions where temperatures drop below 10°C (50°F), grow it as an annual or bring it indoors for overwintering. If overwintering indoors, place the plant in a bright location and reduce watering, refraining from fertilization until new growth emerges in late winter or early spring.
Fertilization
To support rapid growth and continuous flowering, the Giant Potato Tree benefits from regular fertilization during its active growing season. Container-grown plants generally require more frequent fertilization than those in the ground. Apply a balanced liquid fertilizer periodically throughout spring and summer to provide essential nutrients, promoting lush foliage and prolific blooms.
Propagation and Pruning
Propagation Methods
The Giant Potato Tree can be propagated through several methods, with stem cuttings being effective. Select semi-ripe wood sections 5 to 10 cm (2 to 4 inches) long and 0.5 to 1 cm (0.2 to 0.4 inches) thick. Remove all but the top two leaves, cutting them in half to reduce moisture loss. Dip the cut end in rooting hormone and plant cuttings in a damp, well-draining potting mix, maintaining high humidity to aid rooting within a few weeks. Seed propagation is also possible, though plants grown from seed may take longer to flower.
Pruning for Health and Shape
Pruning maintains the health, size, and shape of the Giant Potato Tree. It can be done in fall as growth slows or in spring to encourage new growth. Selective pruning thins a dense crown, preventing leaning and improving overall form. Removing dead, diseased, or crossing branches improves air circulation and directs energy towards healthy growth. For vigorous varieties, cutting back flowering shoots to two or three buds from main stems in spring encourages more prolific blooming and manages sprawling habits.
Fruiting and Edibility
Following its floral display, Solanum wrightii produces small, round, fleshy berries, typically 3 to 4 cm (1.2 to 1.6 inches) in diameter. These fruits are initially green and may mature to a yellow or reddish hue. Despite the plant’s common name, its fruits are toxic and not suitable for human consumption.
Like many Solanaceae family members, the fruits contain toxic alkaloids, such as solanine. Ingestion can lead to adverse effects, including gastrointestinal problems like abdominal pain, vomiting, and hemorrhagic diarrhea. Central nervous system symptoms such as apathy, drowsiness, excessive salivation, tremors, and convulsions can also occur. This plant is cultivated for its ornamental value, and its fruits should be kept away from children and pets.