Family: Acanthaceae
Common name: Black-eyed susan vine, Black-eyed Susan, Black eyed susan vine
Black-eyed Susan is a beautiful climbing vine that can cover your garden with a cascade of bright orange or yellow flowers, the vines climbing on trellises, fences, or supporting structures. They are native to tropical Africa, but can grow well in most tropical countries as ornamental plants.
Plant characteristics
The stems of Black-eyed Susan vines can climb to a height of 3-5 meters with long, green twining stems that are woody at the base, and tender green towards the tips.
Leaves are ovate to heart-shaped, bright green with a slightly wavy margin. Stems, leaves, and buds are covered with thin, white hairs giving them a soft, velvety texture.
Leaves are 5-7 cm long and arranged alternately on the stem, a good contrast to the bright orange flowers. Black-eyed Susan vine flowers are a quite a spectacle, orange or yellow with a dark brown to black center which is actually the corolla tube of the flower.
Each flower is 4-5 cm in diameter with 5 distinct petals that radiate from the dark colored center. They are mostly orange or yellow in color, through there are cultivars with white petals as well.
These plants flower in abundance from late spring to early fall, a very long flowering period during when they attract bees, butterflies, and insects to them.
After pollination, the flowers produce small rounded capsules that contain numerous seeds. The capsules dry up when they mature and split open releasing the seeds.
Gardening Tips
Black-eyed Susan vines prefer full sun or partial shade and well-drained soil. Plant them near trellises, fences, or supporting structures so that the plant can reach their ideal height and flower well.
They vines and flowers might get spoiled if they are trailing on the ground, or they might climb on surrounding plants stunting their growth.
Regular watering depending on the weather, and fertilization every 2-3 weeks is needed to keep the plant healthy and blooming well. There is no need for pruning unless the plant gets leggy or starts dropping leaves.
There are many related plants in the Thunbergia genus, all of them good garden plants for your garden. Some of the notable relatives are Thunbergia grandiflora or Bengal clockvine with white or purple flowers, Thunbergia fragrans or Sweet clockvine with white flowers, Thunbergia erecta or Bush clockvine with bright purple flowers, and Thunbergia mysorensis or Indian clock vine with hanging red or yellow flowers.
Most of the Thunbergia plants can be distinguished by their conical buds with a bulbous base, and their heart-shaped leaves. These plants are named after Carl Peter Thunberg, a Swedish naturalist and an apostle’of Carl Linnaeus, who made the current system of botanical names for plants.
In addition the name Black-eyed Susan is shared by Rudbeckia hirta, but they do not have climbing vines like Thunbergia alata.
Uses of Black-eyed Susan vines
They are mostly grown as ornamental plants, but they have some medicinal uses in traditional herbal medicine in the treatment of headache, cuts, wounds, and conjunctivitis.
Propagation is through seeds and stem cuttings.
Photographed at: Convent garden, London
