King's Mantle

The Thunbergia erecta, or King's Mantle, is a compact West African shrub carrying deep violet-blue trumpet flowers with a clear yellow throat, held singly against small dark green leaves. It flowers almost without pause in warm conditions, and the colour is a genuine blue-violet rather than the mauve most shrubs offer.
It is a standard of Gulf and tropical shrub beds because it stays compact, takes clipping, and keeps producing flowers at eye level along medians and boundary planting.
King's Mantle is one of very few shrubs that will hold a true violet-blue at hedge height for most of the year.