Thunbergia grandiflora is a long-lived (perennial), vigorous, climbing plant that can grow up to 15 m in height when supported by a host tree.
Younger stems are green, hairy (pubescent), and square in cross-section (quadrangular). The older climbing stems are quite thick when mature, and they usually turn brown in colour and become somewhat rounded in shape.
The oppositely arranged leaves are borne on hairy stalks (pubescent petioles) 4-12 cm long. These leaves are variable in shape (8-22 cm long and 3-15 cm wide) and may have broad heart-shaped (cordate) bases, be somewhat triangular in shape, or be roughly egg-shaped in outline with broad end at base (ovate). Their margins are also quite variable, and can range from being almost entire, to being irregularly toothed (crenated) or have several irregular, pointed lobes.
