Bush clock vine

Appearance

Many of the Thunbergiagenus are vines and creepers, but this one is a sprawling shrub. Its blue flowers resemble those of Morning Glory. It has attractive, small, dark green, ovate-elliptic leaves with entire margins, arranged oppositely on thin brown stems, and an abundant display of tubular flowers that in the most common form are a rich purple with a yellow throat. There is also a white-flowering form that is not so robust, and has smaller leaves. Thunbergia erecta will grow to nearly 2 m in both height and width, responds well to regular pruning and can be shaped into a very bushy shrub. The downside of this shaping is a reduction in the number of flowers. The plant prefers full sun and well-drained soil, although it will bloom in partial shade. Propagation is by means of cuttings, seed, or by layering. The plant is deciduous.

The flowers often come as a surprise, as the buds mostly hide in the foliage until the blooms pop out. The flowers grow to about 3 cm long, and may appear singly or in pairs in the leaf axils. They are slightly fragrant. The flower tube is slightly conical at the base, swelling above, and distinctly curved. It flares open into 5 petals.The plant produces rounded seed capsules that end in a beak.

Naming

Thunbergia was named for Carl Peter Thunberg (1743–1828), Swedish naturalist, explorer and pupil of Linnaeus; erecta is from the Latin erectus, upright.