Black-eyed Susan vine Mixed Colours - Climbing Flowers. Thunbergia is a handsome annual climber with orange, white and yellow flowers. The plant can reach up to 10 feet (3m) tall. Can be sown year round in a protected seed-bed or large pot (3 or 4 seeds a pot) in temperatures not below 20°C. Can also be planted out, after mid May, into the garden in a sunny and sheltered place. Blooms all summer long. Buzzy Climbing Flowers Collection